Abstract: In a plate heat exchanger, having double-walled plate formed heat transfer elements (1, 2), adjacent such heat transfer elements are permanently brazed together by means of three different and spaced brazing joints. A first brazing joint surrounds an area, which covers the heat transfer portions (3, 4) of the heat transfer elements and first inlet openings and outlet openings (8, 9) communicating with a flow passage (6) that is formed between said heat transfer portions. A second joint and a third joint surround respective inlet openings and outlet openings (10, 11), which are closed from communication with said flow passage (6). Leakage areas (16-19; 39), which communicate with the surrounding of the plate heat exchanger, are formed between said first joint and each one of said other joints.