Private Functionを関数として利用(戻り値:True/False)

Public Sub test()
Dim i As Long
Dim WrkRange As Variant

If ChkNumber(Range("syain_id"), 3) Then '---- Trueで実行
WrkRange = Sheets("SyainMST").UsedRange
For i = 1 To UBound(WrkRange)
If WrkRange(i, 1) = Range("syain_id") Then
Range("syain_id").Offset(1, 0) = WrkRange(i, 2)
Range("syain_id").Offset(2, 0) = WrkRange(i, 3)
Range("syain_id").Offset(3, 0) = WrkRange(i, 4)
Range("syain_id").Offset(4, 0) = WrkRange(i, 5)
Exit For
End If
Range("hyoji_all").ClearContents '---- 範囲 hyoji_all をclear
Next i
Else
MsgBox "社員IDが有効ではありません", vbCritical
End If
End Sub

Private Function ChkNumber(ByVal pNumber As String, ByVal pKeta As Long) As Boolean
If IsNumeric(pNumber) Then
If Len(pNumber) = pKeta Then
ChkNumber = True
Exit Function
End If
End If
ChkNumber = False
End Function