Sub toto()
Dim tab1
Set tab1 = CreateObject("Scripting.dictionary")
feuille1 = "données"
l = 6
c = 1
While Sheets(feuille1).Cells(l, c) <> ""
cle = Sheets(feuille1).Cells(l, c + 1)
If tab1.exists(cle) Then
tab1(cle) = tab1(cle) & ", " & Sheets(feuille1).Cells(l, c)
Else
tab1(cle) = Sheets(feuille1).Cells(l, c)
End If
l = l + 1
Wend
'-----------------------------------------
' ecriture resultat
'-----------------------------------------
feuille1 = "siqueau"
l = 2
For Each cle In tab1
Sheets(feuille1).Cells(l, 1) = cle
Sheets(feuille1).Cells(l, 2) = tab1(cle)
l = l + 1
Next
End Sub