There is provided a transmitter receiver apparatus in which a directional coupler and single pole double throw (SPDT) switches are includes on the reception side. In the directional coupler, a reception signal is inputted and split into two signals having phases different from each other by 90° and the two split signals are outputted to SPDTs. Each of the SPDTs outputs each of the split signals to an output terminal connected to an amplifier during a passage mode and to a terminal terminated with a predetermined impedance during a blocking mode.