To reduce the size of a measuring instrument and, at the same time, to reduce the manufacturing cost of the instrument.

An actuator 33 is constituted of a fixed section 38 provided with a fixed magnet 44, an exciting coil 45, and a shaft 47 and a mobile section 39 which has a magnet 50 and is held by the shaft 47 in a state where the magnet 50 can freely oscillate and a reflecting mirror 31 is fixed to the mobile section 39. When the coil 45 is excited by making an alternating current to flow to the coil 45, the mobile section 39 oscillates and the reflecting mirror 31 scans a laser beam 3 to convert it into a spot light.