A postal sorting machine includes a sorting conveyor having sorting outlets, a first feed branch adapted for automatically injecting heterogeneous postal articles of the small parcel type into the sorting conveyor, and a second feed branch adapted for injecting homogeneous flat mailpieces of the letter type, or the magazine type, or of some analogous type into the sorting conveyor. The first feed branch has an inlet adapted for receiving the heterogeneous postal articles loose, and it is provided with at least one robotized handling arm of the “pick and place” type.