To effectively utilize a frequency band even in a section in which a radar signal is not received and to improve the using efficiency by intermittently transmitting the signal by a transmitting means of a radar, and transmitting a signal modulated differently from the radar signal during a time in which the radar signal is not transmitted.

Measurements of a distance to a target object 107, a relative speed or the like and a data transmission can be executed by transmitting a signal of a communication signal formed at an SS modulator to an idle section except a radar signal transmitting section produced by a triangular wave generator 101 and a VCO 102. The received signal is used for measuring the distance to the object 107, the relative speed of the like by a mixer 111, an LPF 112 and a frequency analyzer 113 and used for demodulating a base band signal by a phase demodulator 11 and an SS demodulator 116. Even if the received signal includes the radar signal and the communication signal, they do not affect its demodulation since their modulation types are mutually different.