To provide a plate-type heat exchanger capable of increasing efficiency of heat exchange more than a conventional heat exchanger and preventing a can body from being heated up to high temperatures by combustion gas properly.

This plate-type heat exchanger A1 is provided with a plurality of plates 2 for heat exchange laminated in the direction of thickness, a water flow passage 3 formed by the plurality of these plates 2, and the can body 1 having a peripheral wall part 10 surrounding the plurality of plates 2. This heat exchanger A1 is provided with a space part 5 formed in the inward parts of the plurality of plates 2 owing to each plate 2 being like a frame, a plurality of clearances 51 provided between the plurality of plates 2 to let combustion gas pass, and a passage 52 for combustion gas formed among the plurality of plates 2 and the peripheral wall part 10 of the can body 1 so that combustion gas introduced into the space part 5 or generated in the space part 5 passes through the plurality of clearances 51 and flows out into the passage 52 for combustion gas.