Private Sub CommandButton1_Click()
Dim hairetu As Variant
Dim i As Long
Dim maxnum As Long
hairetu = Array("11", "99", "22", "33", "44")
maxnum = -1
For i = 0 To UBound(hairetu)
If hairetu(i) > maxnum Then
maxnum = hairetu(i)
End If
Next i
MsgBox maxnum
End Sub
とします。