A heat exchanger includes flat tubes and corrugated fins. The corrugated fin includes peak portions contacting the adjacent tubes, and flat portions for making air to pass therebetween in an air flow direction. The flat portion has a first area including pairs of end louvers provided in end portions of the flat portion in a width direction between the adjacent tubes, and a flat part provided between the end louvers in the width direction. The pairs of the end louvers are arranged in the flat portion in the air flow direction. The first area is provided at least one of an upstream end portion and a downstream end portion of the flat portion in the air flow direction.