A heat exchanger includes tubes through which a first fluid flows, and a corrugated fin configured to improve a heat exchange efficiency between the first fluid flowing through the tubes and a second fluid flowing outside of the tubes. The corrugated fin includes bending portions connected to adjacent two tubes of the tubes and fin body portions extending between the bending portions. Each of the fin body portions includes grooves on a surface thereof and a protrusion. Each of the grooves extends in an extending direction from one of the adjacent two tubes toward the other. The protrusion is disposed at an intermediate position of at least one of the grooves between the adjacent two tubes in the extending direction. The protrusion protrudes from a bottom of the at least one of the grooves toward the surface.