A heat exchanger is provided with a cooling fin including a plurality of fin portions and a base portion supporting the fin portions, and a plurality of pins press-fitted into the fin portions. In the heat exchanger the pins each having a wider width than each space between the fin portions formed in advance in parallel straight shapes are press-fitted into the spaces in a direction from a top end of each fin portion toward the base portion. Accordingly, the fin portions are formed into corrugated shapes by plastic deformation, thereby fixing the pins between the fin portions in positions apart from the base portion. In each space the pins are arranged at intervals in a longitudinal direction of each space. The pins arranged in adjacent spaces are placed with a displacement in alternating pattern.