感谢JvdV我找到了解决方案，也许它会对某人有用：

Sub test()
Dim ark1 As Worksheet
Dim i As Long, j As Long, lastRow As Long, nextRow As Long, actCell As Long, actCell2 As Long
Set ark1 = Worksheets("Arkusz1")

For i = 1 To 20
    If ark1.Cells(i, "A") = ark1.Cells(1, "B") Then
        ark1.Cells(i, 1).Select
        actCell = ActiveCell.Row
        MsgBox actCell
    End If
Next i

' Next no empty cell
For i = actCell + 1 To 20
        If IsEmpty(ark1.Cells(i, "A")) Then
            Else
            ark1.Cells(i, 1).Select
            actCell2 = ActiveCell.Row
            MsgBox "The active cell is not empty   " & actCell2
            Exit For
        End If
 Next i
End Sub