You Look Too Cool

Sub 選択範囲の全角半角を変換()
  Dim c As Object
  res = InputBox("1:英字を全角から半角 2:英字を半角から全角 3:数字を全角から半角 4:数字を半角から全角", "全角半角変換", "1")
  If res = "1" Then
    For Each c In Selection
      c.Value = alphabet_zen2han(c.Value)
    Next c
  ElseIf res = "2" Then
    For Each c In Selection
      c.Value = alphabet_han2zen(c.Value)
    Next c
  ElseIf res = "3" Then
    For Each c In Selection
      c.Value = number_zen2han(c.Value)
    Next c
  ElseIf res = "4" Then
    For Each c In Selection
      c.Value = number_han2zen(c.Value)
    Next c
  End If
End Sub

Function alphabet_zen2han(moto)
  For i = 1 To Len(moto)
    If Mid(moto, i, 1) Like "[Ａ-Ｚａ-ｚ]" Then
      Mid(moto, i, 1) = StrConv(Mid(moto, i, 1), vbNarrow)
    End If
  Next i
  alphabet_zen2han = moto
End Function

Function alphabet_han2zen(moto)
  For i = 1 To Len(moto)
    If Mid(moto, i, 1) Like "[A-Za-z]" Then
      Mid(moto, i, 1) = StrConv(Mid(moto, i, 1), vbWide)
    End If
  Next i
  alphabet_han2zen = moto
End Function

Function number_zen2han(moto)
  For i = 1 To Len(moto)
    If Mid(moto, i, 1) Like "[０-９]" Then
      Mid(moto, i, 1) = StrConv(Mid(moto, i, 1), vbNarrow)
    End If
  Next i
  number_zen2han = moto
End Function

Function number_han2zen(moto)
  For i = 1 To Len(moto)
    If Mid(moto, i, 1) Like "[0-9]" Then
      Mid(moto, i, 1) = StrConv(Mid(moto, i, 1), vbWide)
    End If
  Next i
  number_han2zen = moto
End Function