To prevent plates 30 from peeling, etc., even if carbon dioxide refrigerant is used.

A plurality of dish-shaped plates 30, coated with a brazing material beforehand are superposed and provided with pressurizing heat treatment, and thereby each plate 30, is brazed at a part where it is brought into contact with each other. The space formed by the upper and lower plates 30 forms a channel, and a plurality of the channels are formed to make carbon dioxide refrigerant and water flow in different channels individually. The channel in which the carbon dioxide refrigerant flows and the channel in which the water flows are alternated with each other, so as to form a plate type heat exchanger performing heat exchanges between them. At this time, a wave part 31 is formed, so that the wave part 31 is extended in a V-shape, as seen from the upside of the plate 30, and that the V-shaped top of the wave part 31 on the upper plate 30 matches with the V-shaped top of the wave part 31 on the lower plate 30, when the plates 30 are superposed.