A radar device including a transmission antenna; a reception antenna; and a controller detecting target information about a target by transmitting a transmission wave from the transmission antenna in multiple transmission/reception modes and by receiving a reception wave by the reception antenna. The multiple transmission/reception modes include: a scanning mode performing beam scanning within a detection angle range; a provisional tracking mode irradiating the transmission wave from the transmission antenna to each of the targets detected in the scanning mode for provisionally detecting target information; and a main tracking mode decisively detecting the target information of each of the targets by irradiating the transmission wave to the target using a transmission wave irradiation time that is set based on the target information provisionally detected in the provisional tracking mode.