To reduce the loss rate of a cell by avoiding the use of an optical delay line.

This ATM switching matrix includes a passive optical core consisting of input and output ports and of photocouplers (Σ1, ..., Σp, Σa, Σr). Each output port (Opj) includes as least p-sets of optical receivers (Fj1, ..., Fjp), one buffer memory (Qj) and distribution assignment means (Fja, Ljr, Fir, Lia) to control switching means (Si1, ..., Sip) of each input port (Ipi) in a way that k-sets of input ports (k is q or below it) receiving k-sets of cells addressed to the same output port (Opj) at a moment are connected to k-sets of different couplers.