A heat exchanger is provided that is capable of performing heat exchange more efficiently by using slits. The heat exchanger includes a refrigerant pipe for allowing a refrigerant to flow therethrough, at least one fin disposed such that the refrigerant pipe penetrates through the at least one fin for performing heat exchange with air passing by the at least one fin, at least one slit formed by partially cutting out the at least one fin, and at least one slit fin extending from the at least one fin adjacent to one side edge of the at least one slit for inducing turbulent flow in air flowing along a flow channel spaced a predetermined distance from the at least one fin. The width of the at least one slit is greater than or equal to 1/3 of the diameter of the refrigerant pipe. Turbulent flow is induced in air flowing through the heat exchanger by one side edge of the slit disposed downstream of the flow direction of air. Consequently, heat exchange efficiency of the heat exchanger is improved.