LASER IRRADIATION DEVICE

To provide a laser irradiation device with suppressed contamination of an optical element which is located on an irradiation object side.SOLUTION: A laser irradiation device 1 comprises: a rotary optical system 33 having an optical element which gives at least one of a deflection angle and a shift amount to a beam B comprising laser beam; and a pressure motor 100 which converts a pressure of a fluid supplied from a fluid supply source 60 into rotational movement, and rotationally drives the rotary optical system. The pressure motor has a high pressure chamber S1 to which the fluid is supplied and of which an internal pressure is higher than the surrounding pressure, and a first bearing 140 and a second bearing 150 which support the rotary optical system rotatably, and are arranged in a center axis direction. The high pressure chamber is so configured that a position thereof in the center axis direction is located on an irradiation object O side with respect to the first bearing and the second bearing.SELECTED DRAWING: Figure 7 【課題】照射対象物側に配置された光学素子の汚損を抑制したレーザ照射装置を提供する。【解決手段】レーザ照射装置１を、レーザ光からなるビームＢに偏角とシフト量との少なくとも一方を与える光学素子を有する回転光学系３３と、流体供給源６０から供給される流体の圧力を回転運動に変換して回転光学系を回転駆動する圧力モータ１００とを備え、圧力モータは、流体が供給され周囲よりも内圧が高圧となる高圧室Ｓ１と、回転光学系を回転可能に支持するとともに、回転中心軸方向に配列された第１軸受１４０及び第２軸受１５０を有し、高圧室は、回転中心軸方向における位置が、第１軸受及び第２軸受に対して照射対象物Ｏ側へ配置される構成とする。【選択図】図７