Almost the same effects of CO₂ laser on objects will be expected after absorption of a quantity of laser energy by irradiation at one time of single pulse or continuous wave, as irradiations dividing it into short pulses. One of the available dividing laser irradiations is repetition pulse laser method which the short laser pulses with the same character irradiate repeatedly. The factors of repetition pulse laser are power, pulse width, repetition cycle, duty, amount of irradiation time and, in addition to them, scanning speed in incision. In clinical application of this technique, these factors must be selected according to practical use. This techniques have many practically available merits as mentioned below. 1) Laser radiation and its effects can be controlled easily. 2) Operation can be controlled easily. 3) The degree of effects of laser on tissues could be controlled easily. 4) Laser therapy without pain is possible.