A rail position measurement device for measuring a three-dimensional position of a rail using a measurement vehicle, said rail position measurement device being provided with: a position and posture measurement device 42 for measuring the position and posture of the measurement vehicle; and a laser scanner 16 that is a sensor for measuring the three-dimensional position of the rail and is mounted onto the measurement vehicle so as to be capable of irradiating laser light onto at least the web and foot portions of the side surface of the rail.
