A receiving part receives, over a plurality of pulse reception sections, the echo of a transmitted pulse in a first range cell after a lapse of a first time period from a pulse transmission, and outputs a first signal based on the received echo. The receiving part also receives, over a plurality of pulse reception sections, the echo of the transmitted pulse in a second range cell after a lapse of a second time period from the pulse transmission, and outputs a second signal based on the received echo. A signal integrating part integrates a first number of first signals and outputs an integration result as a first range integration signal. The signal integrating part also integrates a second number of second signals and outputs an integration result as a second range integration signal. A target detecting part detects, based on the first and second range integration signals, a target.