Abstract: A device is disclosed for distributing a two-phase refrigerating medium mass flow in a plate evaporator (12). The evaporator has a distribution channel (14) at the inlet side which may receive a refrigerating medium mass flow coming from an expansion valve (10) and several mutually spaced exchanger channels (16) which branch off from the distribution channel (14) in a substantially perpendicular direction. In order to ensure a uniform distribution of the refrigerant medium mass flow (28') among the exchanger channels (16), a porous body (38) is arranged in the distribution channel (14) between the refrigerating medium inlet (26) and the branch-off points of the exchanger channels (16). The porous body (38) is advantageously arranged in an outer throttle insert (32) which extends over at least part of the length of the distribution channel and in whose wall are located additional throttle openings (34) that lead to the exchanger channels (16).