PROBLEM TO BE SOLVED: To control a rotary handpiece for laser thermia so as to make temperature for heating an affected part be optimum temperature in all of a probe tip face from the center part to peripheral part of the face.SOLUTION: A rotary handpiece 2 for laser thermia irradiates an affected part with laser light having a predetermined diameter from a tip face 4a of a cylindrical probe 4 by: introducing laser light generated by a laser oscillator to the inside of the probe 4 through an optical fiber 3a and rotating a tip of the optical fiber 3a while making the tip deviate from the shaft center of the probe, inside the probe 4. A reflection film for reflecting the laser light is formed on an inner peripheral side face of the probe 4. Feedback control of output of the laser oscillator is performed on the basis of temperature at an affected part detected by a temperature sensor provided in a tip peripheral part of the probe 4.
