Abstract: A detection device includes a transmitter configured to transmit an electromagnetic wave or a sound wave as a transmission signal, a receiver configured to receive a signal obtained by reflecting the transmission signal from an object, as a reception signal, a mixer configured to mix the transmission signal and the reception signal and output a mixed signal as an intermediate signal, and a detector configured to detect a motion of the object and a distance to the object from the intermediate signal, wherein the detector performs first sampling of the intermediate signal at a first sampling time in a first time interval when detecting the motion of the object, and the detector performs second sampling at a second sampling time in a second time interval smaller than the first time interval, between adjacent first sampling times when detecting the distance to the object.