To provide a shock absorber which can prevent generation of vibration by reversal motion in a case a heating device is move in swing motion at time intervals so as to enable hair treatment promotion to be accurately carried out.

In a heir treatment promotion device, a heater 73 to irradiate infrared rays is attached on a reflecting plate 72 and the reflecting plate 72 is rotated by a motor 3 so as to irradiate infrared rays to the head of a subject around along the top part, the rear part, and both side parts. A resistance is connected to the motor 3 in series to reduce drive torque of the motor 3 at activation and reversal. Thus, shock at activation is reduced.