Abstract: An external container is divided into IF unit 120 as a first flat-type external container that holds T-PA unit 140 provided with transmission power amplifier T-PA which amplifies transmission and reception signals and that is fixed to an installation place, and MDE unit 110 as a second flat-type external container that holds a circuit board of modulation and demodulation equipment (MDE) which modulates and demodulates transmission and reception signals and that is detachably attached to the first external container, MDE unit 110 is disposed on the outside of IF unit 120 with heat dissipation space provided therebetween, and a fin as a radiating member is provided on each of opposite faces of IF unit 120 and MDE unit 110.