A heat exchanger includes a refrigerant pipe in which a refrigerant flows and a heat exchanger fin coupled to the outer circumference of the refrigerant pipe. The heat exchanger fin includes a plate, a protrusion protruding from the plate, slits disposed at opposite sides of the protrusion to guide air to the protrusion, and a louver unit provided at the protrusion to perform heat exchange with the air having passed through the slits.