Sub match_col_a_b()
    Dim x As Integer '重要
    ii = 1
    For i = 1 To Cells(65536, 1).End(xlUp).Row
        On Error Resume Next
        x = Application.Match(Cells(i, 1), Range("b:b"), 0)
        If Not Err <> 0 Then

        Else
            Cells(ii, 3) = Cells(i, 1)
            ii = ii + 1
        End If
    Next
    '---
    ii = 1
    For i = 1 To Cells(65536, 2).End(xlUp).Row
        On Error Resume Next
        x = Application.Match(Cells(i, 2), Range("a:a"), 0)
        If Not Err <> 0 Then

        Else
            Cells(ii, 4) = Cells(i, 2)
            ii = ii + 1
        End If
    Next
End Sub