To provide a laser beam machining apparatus which is capable of reducing cutting time and which has a simple structure.

This invention is related to an apparatus for cutting a semiconductor wafer (workpiece) by irradiating it with a laser beam, comprising a laser light source 10 for generating a laser beam and a condensing lens 12 for converging the laser beam on the semiconductor wafer. The condensing lens 12 includes two lens portions 12a, 12b arranged vertically to the optical axis L of the laser beam, wherein the two lens portions 12a, 12b each has a focal point different in height in the direction of the optical axis L. The condensing lens 12 consists of one lens in which the two lens portions 12a, 12b are integrally formed.