Abstract: The present invention relates to a plate heat exchanger of cross-flow type for heat exchange between different media of which at one is a gas and the other a fluid, wherein the plate heat exchanger comprises plates (8a, 8b) with elongated and in various alternating directions protruding corrugating ridges (15) and wherein the plate heat exchanger has through-flow gaps for a gas and through-flow gaps for a fluid. The plates (8a, 8b) are provided with edge portions and end walls which on different plates (8a, 8b) are positioned in different directions relative to the corrugating ridges (15) of the same plate (8a, 8b respectively). The edge portions and end walls of different plates (8a, 8b) are joined together by means of soldering.