An outdoor unit for an air conditioner, said outdoor unit comprising: a case to form an appearance of the outdoor unit; a heat source disposed in the case, wherein the heat source is a controller to control operation of constituent elements of the air conditioner; and a heat radiation unit connected to the heat source, to radiate heat generated from the heat source, wherein the heat radiation unit comprises a heat radiation member thermally connected to the heat source, to radiate heat generated from the heat source, a refrigerant pipe thermally connected to the heat radiation member while being formed therein with a channel, through which refrigerant flows, a pipe jacket coupled to the heat radiation member, and formed with a receiving groove to receive a portion of the refrigerant pipe, a cover bracket to press the portion of the refrigerant pipe received in the receiving groove of the pipe jacket in a downward direction of the receiving groove, characterized in that the outdoor unit comprises a support member coupled to the heat radiation member, to fix the heat radiation member at a required position, and formed with a fitting hole to receive the heat radiation member, wherein the heat radiation member is arranged opposite the controller with reference to the support member; at least a portion of the heat radiation member extends through the fitting hole, and contacts the controller; and the heat radiation member comprises: a contact portion extending through the fitting hole, to contact the controller; and a coupling portion extending outwards from the contact portion, to overlap the support member forming a peripheral edge of the fitting hole, wherein the contact portion protrudes beyond the support member toward the controller, and wherein the coupling portion and the support member are bolted together. a case to form an appearance of the outdoor unit; a heat source disposed in the case, wherein the heat source is a controller to control operation of constituent elements of the air conditioner; and a heat radiation unit connected to the heat source, to radiate heat generated from the heat source, wherein the heat radiation unit comprises a heat radiation member thermally connected to the heat source, to radiate heat generated from the heat source, a refrigerant pipe thermally connected to the heat radiation member while being formed therein with a channel, through which refrigerant flows, a pipe jacket coupled to the heat radiation member, and formed with a receiving groove to receive a portion of the refrigerant pipe, a cover bracket to press the portion of the refrigerant pipe received in the receiving groove of the pipe jacket in a downward direction of the receiving groove, characterized in that the outdoor unit comprises a support member coupled to the heat radiation member, to fix the heat radiation member at a required position, and formed with a fitting hole to receive the heat radiation member, a heat radiation member thermally connected to the heat source, to radiate heat generated from the heat source, a refrigerant pipe thermally connected to the heat radiation member while being formed therein with a channel, through which refrigerant flows, a pipe jacket coupled to the heat radiation member, and formed with a receiving groove to receive a portion of the refrigerant pipe, a cover bracket to press the portion of the refrigerant pipe received in the receiving groove of the pipe jacket in a downward direction of the receiving groove, characterized in that the outdoor unit comprises a support member coupled to the heat radiation member, to fix the heat radiation member at a required position, and formed with a fitting hole to receive the heat radiation member, wherein the heat radiation member is arranged opposite the controller with reference to the support member; at least a portion of the heat radiation member extends through the fitting hole, and contacts the controller; and the heat radiation member comprises: a contact portion extending through the fitting hole, to contact the controller; and a coupling portion extending outwards from the contact portion, to overlap the support member forming a peripheral edge of the fitting hole, wherein the contact portion protrudes beyond the support member toward the controller, and wherein the coupling portion and the support member are bolted together. a contact portion extending through the fitting hole, to contact the controller; and a coupling portion extending outwards from the contact portion, to overlap the support member forming a peripheral edge of the fitting hole, wherein the contact portion protrudes beyond the support member toward the controller, and wherein the coupling portion and the support member are bolted together.