An antenna integral-type transmitter/receiver system to be installed outdoors and used for transmission and reception of radio signals. The object is to provide a small, lightweight antenna integral-type transmitter/receiver system formed of the reduced number of parts and assembling steps. The antenna integral-type transmitter/receiver system consists of a housing having one end surface in which an opening is formed and the other end surface in which an antenna mounting surface is formed, and including a transmitter/receiver function unit formed of a waveguide circuit unit, a high-frequency electrical circuit unit, and an intermediate frequency electrical circuit unit; an antenna connected to the transmitter/receiver function unit mounted on the other end surface of the housing; and a cover member for closing the opening of the one end surface of the housing. The waveguide circuit unit and the high-frequency electrical circuit unit form a first unit. The intermediate frequency electrical circuit unit forms a second unit. The first unit and the second unit are arranged so as to be stacked in the housing.