LASER PROCESSING DEVICE AND METHOD FOR PROCESSING WORKPIECE

This laser processing device is provided with: a placement table for placing a workpiece; a shaping optical system that shapes a laser beam so that an irradiation region of the laser beam has a rectangular shape having short sides and long sides in a mask configured to shield a portion of the laser beam, the shaping optical system being capable of changing a second irradiation width of the irradiation region in the direction parallel to the long sides independently of a first irradiation width of the irradiation region in a direction parallel to the short sides, and the shaping optical system being configured to be capable of moving the irradiation region in the direction parallel to the long sides; a projecting optical system configured to project a pattern of the mask onto the workpiece placed on the placement table; and a moving device configured to be capable of moving the irradiation region in the direction parallel to the short sides. 激光加工装置具有：载置台，其载置被加工物；整形光学系统，其对激光进行整形，以使激光在掩模中的照射区域成为具有短边和长边的矩形状，所述掩模构