A laser beam applying unit of a laser processing apparatus includes a laser oscillator, a condenser adapted to focus the laser beam emitted from the laser oscillator and apply the laser beam to a workpiece, and a liquid jetting apparatus disposed at a lower end portion of the condenser and adapted to jet a liquid to an upper surface of the workpiece. The liquid jetting apparatus includes: a transparent plate disposed at the lower end portion of the condenser and permitting transmission therethrough of the laser beam; a casing provided with a space defined by a ceiling wall composed of the transparent plate, side walls, and a bottom wall; an opening formed in the bottom plate, extending in a processing feeding direction, and permitting passage therethrough of the laser beam focused by the condenser; and a liquid supply section adapted to supply the liquid to the casing.