The laser the organism hard the heat quantity which is given to organization and the organization around that is not too large with low power output, the organism it can grant the resistance to acid to organization hard, being small-sized, is easy to handle, low the laser device and the like which is price offers. The radiation vessel and one end which radiation are done are connected the aforementioned laser by the aforementioned radiation vessel the organism which includes inorganic crystal haidorokishiapataito hard in the laser device in order to irradiate the laser to organization, other than derived optical expedient and the aforementioned derived optical expedient which the aforementioned laser derived light are done is connected by the edge in the other edge and the aforementioned laser output of the lighting vessel and the aforementioned laser which the aforementioned organism hard are irradiated to organization below 1.2W, power density is below 12.0W/cm2 above 0.8W/cm2, at the same time in order, for energy density to be below 50.0J/cm2 above 1.7J/cm2, control of the lighting which controls the lighting of the laser from the aforementioned lighting vesselIt provides with expedient.レーザーが低出力で生体硬組織やその周辺組織に与える熱量が大きすぎず、生体硬組織への耐酸性の付与を行い得る、小型で扱い易く、低価格であるレーザー装置等を提供する。無機結晶ハイドロキシアパタイトを含む生体硬組織へレーザーを照射するためのレーザー装置において、前記レーザーを出射する出射器と、一端が前記出射器に接続され、他端に前記レーザーを導光する導光手段と、前記導光手段の他端に接続され前記レーザーを前記生体硬組織へ照射する照射器と、前記レーザーの出力が1.2W以下で、パワー密度が0.8W/cm2以上12.0W/cm2以下で、かつ、エネルギー密度が1.7J/cm2以上50.0J/cm2以下となるよう、前記照射器からのレーザーの照射を制御する照射制御手段とを設ける。
