'拡張子を取得
Private Function ExGetExt(sfina As String) As String
Dim i As Long
Dim s1 As String
ExGetExt = ""
'ファイル名の最後の文字から「.」を探す
For i = Len(sfina) To 1 Step -1
If Mid(sfina, i, 1) = "." Then
'拡張子を取得
ExGetExt = Mid(sfina, i + 1)
Exit For
End If
Next
End Function