A laser processing apparatus including a laser oscillator, a beam expander, and a light converging system. An output-end-side optical component formed by the beam expander and the light converging system includes one light converging system having composite characteristics of the optical component and the light converging system. Accordingly, the number of lenses used is reduced, the absorption loss of the laser output is lowered, and the number of parts used is reduced. Also disclosed is a laser processing apparatus in which an optical component forming a beam expander is formed partially of an output coupling mirror of the laser oscillator, whereby the number of lenses used is reduced.