The present invention realizes stable operation of a radar device even if there is radio wave interference between multiple radar devices. A radar device 108 is provided with the following: an oscillator 105 that generates a modulated signal that has undergone frequency modulation; a transmission unit 103 that emits a transmission signal that has undergone frequency modulation during a prescribed modulation operation period using the modulated signal generated by the oscillator 105; a reception unit 104 that receives a reception signal which is the transmission signal that has been reflected off of an object in the area; and a signal processing unit 106. The signal processing unit 106 is provided with: an object information calculation unit that calculates information of an object on the basis of the reception signal; an interference state analysis unit that measures a surrounding radio wave interference state, from a prescribed minimum frequency Fmin to a maximum frequency Fmax, during a search modulation operation period that does not overlap the modulation operation period; and a band selection unit that selects a frequency band of the transmission signal on the basis of the radio wave interference state measured by the interference state analysis unit.