In one embodiment, a dimension measurement apparatus has a camera a processing device. The processing device acquires a distance image of an object to be measured which is to be generated by the camera. The processing device divides the distance image into an X coordinate image, a Y coordinate image, and a Z coordinate image, removes a coordinate point not corresponding to one reference surface of the object to be measured, in the respective coordinate images, and detects coordinate images of the reference surface corresponding to the reference surface. |