High intensity ultrasound energy is transmitted to the skin at a depth of 1.5 to 13mm below the surface of the skin to generate a thermal coagulation area, the size of which is of less than 1mm. At the thermal coagulation area, a high heat of more than 60 degrees is generated. By constantly forming the thermal coagulation point on the target layer, the area is regenerated by pulling and shrinking the surrounding skin tissues.