This invention relates to a mail item receiving device for receiving the mail items ejected through an exit slot of a folding and inserting machine, comprising a support plate on which the ejected mail items will accumulate, a front wall on which these mail items will abut upon their ejection, two lateral walls and a rear wall intended to align these mail items once they have fallen on the support plate, said support plate comprising two hollows made on either side of its longitudinal axis at the level of its join with said front wall, the two lateral walls each comprising an opening, at the level of each hollow and over the whole of their height, and the rear wall comprises hooking means for connecting the receiving device to the folding and inserting machine.