Sub Conversion()
Columns("C:D").Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
With Range(Cells(12, 2), Cells(Rows.Count, 2).End(xlUp))
.TextToColumns Destination:=Range("B12"), DataType:=xlFixedWidth, _
OtherChar:="/", FieldInfo:=Array(Array(0, 1), Array(8, 9), Array(9, 1)), _
TrailingMinusNumbers:=True
With .Offset(, 2)
.FormulaR1C1 = "=RC[-2]+RC[-1]"
.NumberFormatLocal = "jj/mm/aaaa hh:mm:ss"
.Value = .Value
End With
End With
End Sub