A radar device includes a transmission module that generates a transmission chirp signal synchronized with a timing signal, and reception modules that each receive a reflected wave and a direct wave of the transmission chirp signal emitted from the transmission module, and perform mixing on a received signal, using a reception chirp signal, the reception chirp signal being synchronized with the timing signal and having the same slope as the transmitted chirp signal. The radar device includes a signal processor that detects a target on the basis of a beat signal resulting from the mixing performed by the reception modules. The signal processor detects a level of the beat signal generated from the received direct wave from the transmission module to the reception modules. The signal processor determines a failure of the radar device by comparing the detected level with a threshold.