Private Sub UserForm_Initialize()

    Dim 부서 As Range, 셀 As Range
    Dim 고유항목 As New Collection, 항목 As Variant
    
    Set 부서 = Range("D3", Cells(Rows.Count, "D").End(xlUp))

    On Error Resume Next
    
        For Each 셀 In 부서
            
            고유항목.Add Item:=셀.Value, Key:=셀.Value
        
        Next

    On Error GoTo 0

    With ComboBox1
        
        For Each 항목 In 고유항목
        
            .AddItem 항목
        
        Next
    
        .ColumnWidths = .Width
        .ListWidth = .Width
    
    End With

End Sub