A heat exchanger comprising a plurality of refrigerant pipes bent many times for passing a refrigerant for heat exchange; and cooling fins arranged at an outer circumference surface of the refrigerant pipes for expanding a contact area of air which passes through the refrigerant pipes, wherein a direction that the refrigerant pipes are bent is a major axis and a perpendicular direction to the major axis is a minor axis. In the heat exchanger, a bending portion of the refrigerant pipe is prevented from being distorted thus to have a smooth refrigerant flow and enhance a heat exchange performance.