There is provided a radar device. A transmitting unit transmits a transmission signal in which an up period and a down period are repeated. A receiving unit receives reception signals from a target. A distance measuring unit computes the distance between the target and the radar device based on a reception signal corresponding to the up period, as an up-side distance, and computes the distance between the target and the radar device based on a reception signal corresponding to the down period, as a down-side distance. An aliasing determining unit determines whether velocity aliasing has occurred, based on the up-side distance and the down-side distance. A velocity measuring unit computes the relative velocity between the target and the radar device, based on the result of determination on velocity aliasing, and one of the reception signal of the up period and the reception signal of the down period.