A plate heat exchanger reduces the cross-sectional diameter of channels and suppresses clogging of the channels with a brazing material. First heat transfer plates each include a plurality of rows of inverse V-shaped waves formed on its surface, and second heat transfer plates each include a plurality of rows of V-shaped waves formed on its surface are alternately stacked. The intersections of the waves are joined by brazing. Further, a distance (L) between joint points in the short-axis direction of the heat transfer plates and a fillet dimension (f) in the short-axis direction of the heat transfer plates satisfy a relation 0≤((L−f)/L)×100≤40.