The invention relates to a plate-type heat exchanger, in which at least one first flow passage (16) for a first medium is provided between two plates (12 and 14), which form a plate pair (13). A plurality of second flow passages (18), which are connected in parallel, for a second medium are provided between two plate pairs (13). To provide a novel, improved heat exchanger, which is easier to produce, it is proposed that the second, parallel-connected flow passages (18) are formed in each case by one plate (14, 12) from adjacent plate pairs (13).