An optical fiber that transmits scanning light to a subject a housing holding the optical fiber a vibration element fixed to an exit end part of the fiber and vibrating periodically the exit end part so that the scanning light emitted from the exit end part scans on the subject in a predetermined trajectory a hollow tube formed so an inner circumferential surface of the hollow tube positioned outside a moving range of the exit end part and the vibration element surrounds an entire circumference of the exit end part and a movable part of the vibration element a thermal detection sensor detecting temperature in a hollow space of the hollow tube and a heating element laid on one of the inner and outer circumferential surface of the hollow tube and increases the temperature in the hollow space in response to the temperature detected by the thermal detection sensor.
