PURPOSE: To achieve suitable control for high speed switching of beam, by storing the amount of phase set of each phase shifter to a memory circuit, performing readout/write-in in the specified timing in synchronizing with transmission trigger, and performing the phase set of each phase shifter.

CONSTITUTION: The amount of phase set of a total phase shifter 2 corresponding to a beam number is stored in a phase storage circuit 11 corresponding to a driver number, transmission frequency and beam number. A control circuit 10 forms various timings to control the circuit 11 and a driver circuit group 9 by receiving the transmission trigger from a radar reference signal generating section, transmission frequency designation signal and beam number designation signal in synchronizing with this trigger. Further, the circuit group 9 generates the driving current corresponding to the amount of phase to be set to the phase shifter 2 corresponding to the various timings. Next, the amount of set phase of the phase shifter 2 corresponding to the beam number and frequency is sequentially read out from the circuit 11 to the circuit group 9 to form the beam by adding the driving current to the total phase shifter 2 immediately after the start of the transmission and reception.