To simultaneously realize high long-distance sensitivity and wide dynamic range by converting RF signals distributed into plural ones, after respectively amplifying, to IF signals by corresponding respective mixers, and compounding the respective IF signals.

This radar device 30 is provided with a receiver part 32 distributing a received signal into plural ones to process them. For example, a received RF signal supplied to a front end part 40 is input to a directional coupler 44, in a through line, it is supplied to a low noise amplifier 46 of relatively high gain as the RF signal hardly having attenuation, and in an attenuation line, it is supplied to a low noise amplifier 48 of relatively low gain as the signal attenuated by about -30 dB for example. A transmission passage containing the amplifier 46 is designed so that minimum signal level characteristic capable of discriminating noise and a signal becomes best, and a transmission passage containing the amplifier 48 bas high saturation level. The respective amplified RF signals are converted to IF signals by mixers 52, 54, they are compounded by a specified method in a IF part 60, and it is supplied to an output terminal 62.