There is provided a distance measurement device that can successfully take in reflected light from a distance measurement area, and at the same time, can achieve compactness of the distance measurement device. The distance measurement device includes a fixed part, a rotating part that is rotatably disposed on the fixed part, a laser light source that is disposed in the fixed part, and a photodetector that is disposed in the fixed part. The distance measurement device further includes a beam splitter that is disposed in the fixed part and separates an optical path of projection light emitted from the laser light source from an optical path of reflected light reflected by a distance measurement area and an imaging lens that is disposed in a common optical path of projection light and reflected light and is used for taking in reflected light reflected by the distance measurement area.