To obtain a control apparatus by which antennas at a plurality of radar devices are turned synchronously, by which their beams are not overlapped geometrically and by which the generation of a ghost is reduced by generating antenna rotation signals whose phase difference is different from an identical reference signal.

A pulse signal is output from a reference-frequency generator 4 so as to be input to a first frequency divider 5a and a second frequency divider 5b. The frequency divider 5a turns a first antenna 9a, the frequency divider 5b turns a second antenna 9b in such a way that the pulse signal is provided with a required phase difference θ so as to be used as a rotation instruction signal. Consequently, the antenna 9a at a first radar device 1a and the antenna 9b at a second radar device 1b are turned by keeping the phase difference θ. As a result, also beams of the devices 1a, 1b keep the constant phase difference θ so as not to overlap each other geometrically. Then, the generation of a ghost or the like due to the interference of radio waves is reduced, and input information from the plural devices 1a, 1b can have consistency in terms of time.