Electronic device includes a housing; an antenna module accommodated in the housing, the antenna module including a PCB including a first side and a second side opposite to the first side; one or more antenna elements disposed at the first side of the PCB; and a wireless communication circuit disposed at the second side of the PCB and configured to transmit and/or receive a radio signal through an antenna element of the one or more antenna elements; and a conductive member accommodated in the housing and including a supporting portion and a connecting portion extended from the supporting portion and connected to the conductive portion of the housing, the supporting portion configured to support the antenna module such that the first side of the PCB faces in a direction toward the lateral surface of the electronic device, and the connecting portion including a hole through which a fastening member is disposed to fasten the conductive member to the conductive portion of the housing. Heat generated by the antenna module is transferred to the conductive portion of the housing.