A radar device (1) includes a frequency conversion part (12) which converts a frequency of an echo signal obtained by reflecting a detection signal and receiving the reflected detection signal by an antenna (10), and amplifies a signal level thereof. The radar device (1) includes a path switching part (20) which outputs, as a calibration signal, to the frequency conversion part (12), the transmission signal output by the transmission signal generation part (11) at a timing while the transmission signal is output to the antenna (10). A gain adjustment part (23) changes an amplification gain of the frequency conversion part (12) on the basis of a signal level of the calibration signal input to the frequency conversion part (12) and a signal level of the calibration signal having been amplified by the frequency conversion part (12).