Excel VBA テクニック集
列番号対応表

Public Function Excel_RetuToNum(Retu_F As String) As Integer
    Excel_RetuToNum = 0               
    If Len(Retu_F) = 1 Then
        Excel_RetuToNum = Num_From_Alphabet(Retu_F)
        End If
    If Len(Retu_F) = 2 Then
        Excel_RetuToNum = Num_From_Alphabet(Mid(Retu_F, 1, 1)) * 26 _
                        + Num_From_Alphabet(Mid(Retu_F, 2, 1))
        End If
    If Len(Retu_F) = 3 Then
        Excel_RetuToNum = Num_From_Alphabet(Mid(Retu_F, 1, 1)) * 26 * 26 _
                        + Num_From_Alphabet(Mid(Retu_F, 2, 1)) * 26 _
                        + Num_From_Alphabet(Mid(Retu_F, 3, 1))
        End If
End Functionkkk

Public Function Num_From_Alphabet(Alpha_F As String) As Integer
    Const Alpha_T = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    Num_From_Alphabet = 0
    If Len(Alpha_F) <> 1 Then
        Exit Function
        End If
    Num_From_Alphabet = InStr(Alpha_T, UCase(Alpha_F))
End Function

Public Function Excel_NumToRetu(Num_F As Integer) As String
    Dim Num_W As Integer
    Dim Num1_W As Integer
    Dim Num2_W As Integer
    Dim Num3_W As Integer
    Dim Num4_W As Integer
    
    Excel_NumToRetu = ""
    If Num_F < 1 Then
        Exit Function
        End If
        
    If Num_F <= 26 Then
        Excel_NumToRetu = Num_To_Alphabet(Num_F)
        Exit Function
        End If
        
    If Num_F <= 27 * 26 Then
        Num_W = Num_F - 1
        Num1_W = Int(Num_W / 26)
        Num2_W = Num_W - Num1_W * 26 + 1
        Excel_NumToRetu = Num_To_Alphabet(Num1_W) _
                        & Num_To_Alphabet(Num2_W)
        Exit Function
        End If
        
    If Num_F <= 27 * 27 * 26 Then
        Num_W = Num_F - 1 - 26
        Num1_W = Int(Num_W / (26 * 26))
        Num_W = Num_W - Num1_W * 26 * 26
        Num2_W = Int(Num_W / 26) + 1
        Num3_W = Num_W - (Num2_W - 1) * 26 + 1
        Excel_NumToRetu = Num_To_Alphabet(Num1_W) _
                        & Num_To_Alphabet(Num2_W) _
                        & Num_To_Alphabet(Num3_W)
        Exit Function
        End If
End Function

Public Function Num_To_Alphabet(Num_F As Integer) As String
    Const Alpha_T = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    Num_To_Alphabet = Mid(Alpha_T, Num_F, 1)
End Function