PURPOSE: To generate a simulation target received signal without actual radiation of radio wave from an antenna in the operation test of a radar system by incorporating a simulation target signal generator into the radar system to enable automatic setting of simulation target signal level sequentially.

CONSTITUTION: The titled device utilizes that the target received signal is described as function of a beam pattern, the radar effective reflection area and the distance to the target. A random noise outputted from a random noise generator 14 is added to a target video level with an adder 12 and outputted to a signal transmitter 11. The signal transmitter 11 generates a signal level equivalent to a distance channel signal of a monopulse comparator based on a target distance gate signal and a distance video level from a target video level converter 13 and the signal level is distributed into an elevation channel signal and an azimuth channel signal and inputted into a phased array antenna 1.