A plate heat exchanger performs heat exchange using a plurality of stacked heat transfer plates. Each heat transfer plate comprises a plate body, an inlet for a first medium, an outlet for the first medium, an inlet for a second medium, an outlet for the second medium, and a projection that forms a channel. At least one of the inlet for the first medium and the outlet for the first medium is disposed in one of the two corners on the one side of the plate body that is in contact with the projection. At least one of the inlet for the second medium and the outlet for the second medium is disposedin one of the two corners on the other side of the plate body that is away from the projection.