テスト

Option Explicit
'--------------------------------------------------------
' C列の値が …
' ①「2025/1-2025/4」→
' ・元セルを「2025/1-2025/3」に書換
' ・直下に1行挿入し C列へ「2025/4」
'
' ②「2025/1-2025/5」→
' ・元セルを「2025/1-2025/3」に書換
' ・直下に1行挿入し C列へ「2025/4-2025/5」
'
' それ以外のセルは触りません。
'--------------------------------------------------------
Sub Split_2025_Ranges_C()

Dim ws As Worksheet
Dim lastRow As Long, r As Long
Dim txt As String

Set ws = ActiveSheet                    '←必要なら固定
Application.ScreenUpdating = False      '画面チラつき防止

lastRow = ws.Cells(ws.Rows.Count, "C").End(xlUp).Row

'▼ 後ろから上へループ（行挿入で行番号がズレないように）
For r = lastRow To 1 Step -1
    txt = Trim$(ws.Cells(r, "C").Value)
    
    Select Case txt
        
        Case "2025/1-2025/4"
            '―― 元セルを修正 ――
            ws.Cells(r, "C").Value = "2025/1-2025/3"
            
            '―― 1行挿入し「2025/4」 ――
            ws.Rows(r + 1).Insert Shift:=xlDown, _
                                CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "C").Value = "2025/4"
            
        Case "2025/1-2025/5"
            '―― 元セルを修正 ――
            ws.Cells(r, "C").Value = "2025/1-2025/3"
            
            '―― 1行挿入し「2025/4-2025/5」 ――
            ws.Rows(r + 1).Insert Shift:=xlDown, _
                                CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "C").Value = "2025/4-2025/5"
            
        '▼他パターンは何もしない
    End Select
Next r

Application.ScreenUpdating = True

End Sub

Option Explicit

Sub Split_2025_Ranges_B()

Dim ws As Worksheet
Dim lastRow As Long, r As Long
Dim txt As String

Set ws = ActiveSheet                '← 必要なら固定
Application.ScreenUpdating = False  '画面チラつき防止

lastRow = ws.Cells(ws.Rows.Count, "B").End(xlUp).Row

'▼ 後ろから上へ（行挿入で行番号がずれても安全）
For r = lastRow To 1 Step -1
    
    txt = Trim$(ws.Cells(r, "B").Value)
    
    Select Case txt
        
        '──────── 1Q + 1 行 ────────
        Case "2025/1-2025/4"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4"
        
        Case "2025/1-2025/6"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4-2025/6"
        
        '──────── 1Q + 2 行 ────────
        Case "2025/1-2025/7"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4-2025/6"
            ws.Cells(r + 2, "B").Value = "2025/7"
        
        Case "2025/1-2025/8"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4-2025/6"
            ws.Cells(r + 2, "B").Value = "2025/7-2025/8"
        
        Case "2025/1-2025/9"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4-2025/6"
            ws.Cells(r + 2, "B").Value = "2025/7-2025/9"
        
        '──────── 1Q + 3 行 ────────
        Case "2025/1-2025/10"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4-2025/6"
            ws.Cells(r + 2, "B").Value = "2025/7-2025/9"
            ws.Cells(r + 3, "B").Value = "2025/10"
        
        Case "2025/1-2025/11"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4-2025/6"
            ws.Cells(r + 2, "B").Value = "2025/7-2025/9"
            ws.Cells(r + 3, "B").Value = "2025/10-2025/11"
        
        Case "2025/1-2025/12"
            ws.Cells(r, "B").Value = "2025/1-2025/3"
            ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
            ws.Cells(r + 1, "B").Value = "2025/4-2025/6"
            ws.Cells(r + 2, "B").Value = "2025/7-2025/9"
            ws.Cells(r + 3, "B").Value = "2025/10-2025/12"
        
        '──────── 何もしない ────────
        Case Else
            '対象外はスキップ
    End Select
    
Next r

Application.ScreenUpdating = True

End Sub

Option Explicit
'--------------------------------------------------------
' ◆ C 列専用版 ◆
' C 列に下記いずれかの文字列があるときだけ処理
'
' 2025/1-2025/4 → 元セル: 2025/1-2025/3
' +1 行: 2025/4
'
' 2025/1-2025/6 → 元セル: 2025/1-2025/3
' +1 行: 2025/4-2025/6
'
' 2025/1-2025/7 → 元セル: 2025/1-2025/3
' +2 行: 2025/4-2025/6 / 2025/7
'
' 2025/1-2025/8 → 元セル: 2025/1-2025/3
' +2 行: 2025/4-2025/6 / 2025/7-2025/8
'
' 2025/1-2025/9 → 元セル: 2025/1-2025/3
' +2 行: 2025/4-2025/6 / 2025/7-2025/9
'
' 2025/1-2025/10 → 元セル: 2025/1-2025/3
' +3 行: 2025/4-2025/6 / 2025/7-2025/9 / 2025/10
'
' 2025/1-2025/11 → 元セル: 2025/1-2025/3
' +3 行: 2025/4-2025/6 / 2025/7-2025/9 / 2025/10-2025/11
'
' 2025/1-2025/12 → 元セル: 2025/1-2025/3
' +3 行: 2025/4-2025/6 / 2025/7-2025/9 / 2025/10-2025/12
'--------------------------------------------------------
Sub Split_2025_Ranges_C()

Dim ws As Worksheet
Dim lastRow As Long, r As Long, txt As String

Set ws = ActiveSheet
Application.ScreenUpdating = False

lastRow = ws.Cells(ws.Rows.Count, "C").End(xlUp).Row

'―― 後ろから上へ走査（行挿入ズレ防止） ――
For r = lastRow To 1 Step -1
    txt = Trim$(ws.Cells(r, "C").Value)
    
    Select Case txt
    '──────── 1Q + 1 行 ────────
    Case "2025/1-2025/4"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4"
        
    Case "2025/1-2025/6"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
    
    '──────── 1Q + 2 行 ────────
    Case "2025/1-2025/7"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7"
        
    Case "2025/1-2025/8"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/8"
        
    Case "2025/1-2025/9"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
    
    '──────── 1Q + 3 行 ────────
    Case "2025/1-2025/10"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
        ws.Cells(r + 3, "C").Value = "2025/10"
        
    Case "2025/1-2025/11"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
        ws.Cells(r + 3, "C").Value = "2025/10-2025/11"
        
    Case "2025/1-2025/12"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
        ws.Cells(r + 3, "C").Value = "2025/10-2025/12"
        
    '──────── それ以外は無視 ────────
    End Select
Next r

Application.ScreenUpdating = True

End Sub

Option Explicit
'--------------------------------------------------------
' ◆ C 列専用版 ◆
' C 列に下記いずれかの文字列があるときだけ処理
'
' 2025/1-2025/4 → 元セル: 2025/1-2025/3
' +1 行: 2025/4
'
' 2025/1-2025/6 → 元セル: 2025/1-2025/3
' +1 行: 2025/4-2025/6
'
' 2025/1-2025/7 → 元セル: 2025/1-2025/3
' +2 行: 2025/4-2025/6 / 2025/7
'
' 2025/1-2025/8 → 元セル: 2025/1-2025/3
' +2 行: 2025/4-2025/6 / 2025/7-2025/8
'
' 2025/1-2025/9 → 元セル: 2025/1-2025/3
' +2 行: 2025/4-2025/6 / 2025/7-2025/9
'
' 2025/1-2025/10 → 元セル: 2025/1-2025/3
' +3 行: 2025/4-2025/6 / 2025/7-2025/9 / 2025/10
'
' 2025/1-2025/11 → 元セル: 2025/1-2025/3
' +3 行: 2025/4-2025/6 / 2025/7-2025/9 / 2025/10-2025/11
'
' 2025/1-2025/12 → 元セル: 2025/1-2025/3
' +3 行: 2025/4-2025/6 / 2025/7-2025/9 / 2025/10-2025/12
'--------------------------------------------------------
Sub Split_2025_Ranges_C()

Dim ws As Worksheet
Dim lastRow As Long, r As Long, txt As String

Set ws = ActiveSheet
Application.ScreenUpdating = False

lastRow = ws.Cells(ws.Rows.Count, "C").End(xlUp).Row

'―― 後ろから上へ走査（行挿入ズレ防止） ――
For r = lastRow To 1 Step -1
    txt = Trim$(ws.Cells(r, "C").Value)
    
    Select Case txt
    '──────── 1Q + 1 行 ────────
    Case "2025/1-2025/4"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4"
        
    Case "2025/1-2025/6"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
    
    '──────── 1Q + 2 行 ────────
    Case "2025/1-2025/7"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7"
        
    Case "2025/1-2025/8"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/8"
        
    Case "2025/1-2025/9"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 2).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
    
    '──────── 1Q + 3 行 ────────
    Case "2025/1-2025/10"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
        ws.Cells(r + 3, "C").Value = "2025/10"
        
    Case "2025/1-2025/11"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
        ws.Cells(r + 3, "C").Value = "2025/10-2025/11"
        
    Case "2025/1-2025/12"
        ws.Cells(r, "C").Value = "2025/1-2025/3"
        ws.Rows(r + 1 & ":" & r + 3).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
        ws.Cells(r + 1, "C").Value = "2025/4-2025/6"
        ws.Cells(r + 2, "C").Value = "2025/7-2025/9"
        ws.Cells(r + 3, "C").Value = "2025/10-2025/12"
        
    '──────── それ以外は無視 ────────
    End Select
Next r

Application.ScreenUpdating = True

End Sub