C'est bon solution trouver. J'ai mis une condition dans mon premier comboBox.
Private Sub ComboBox1_Change()
Dim Mondico As Object
Dim j As Long
Cbo_1.Clear
If Me.ComboBox1.ListIndex = -1 Then Exit Sub
Set Ws = Sheets("Feuil2")
Set Mondico = CreateObject("Scripting.dictionary")
For j = 3 To Ws.Range("A" & Rows.Count).End(xlUp).Row
If Ws.Range("A" & j) = Me.ComboBox1 Then Mondico(Ws.Range("B" & j).Value) = ""
Next j
'Ajout des Sous-Equipements dans Cbo_1
If Mondico.Count > 0 Then
Me.Cbo_1.List = Application.Transpose(Mondico.keys)
End If
End Sub