Abstract: This invention relates to a YAG laser working machine, and an object thereof is to enable highly precise processing such as one required for processing of a photomask which is used at, for example, a step of manufacturing semiconductors. The YAG laser working machine according to this invention is such that a machine body is provided with restriction means for reducing a beam diameter of a laser beam, is provided with shutter means for executing ON.multidot.OFF control of application of the laser beam at a location on the outside of the oscillator, and is provided with highly harmonizing means for the laser beam. A base disk on which the machine body is mounted is formed of solid stone, and is mounted on a plurality of legs through interposition of respective pneumatic springs. Pulse signals regarding the X-movement and the Y-movement of an XY-table are processed by an OR circuit. Pulse application of the laser beam is controlled on the basis of the signals processed by the OR circuit.