To provide a laser beam machining method capable of smoothly removing a low-k film on streets formed on a semiconductor substrate and metallic patterns for testing partially disposed on the streets.

The laser beam machining method for a semiconductor wafer 20 which is laminated with the low dielectric constant insulator film 213 on the surface of the semiconductor substrate 21, is formed with a plurality of circuits 121 by the streets 211 formed like a grid and is partially disposed with the metallic patterns 214 for testing on the streets includes a metallic pattern coordinate setting process of setting the coordinate values of the metallic patterns 214 for testing disposed on the streets 211 of the semiconductor wafer 20 and a laser beam machining process of removing the metallic patterns for testing and the low dielectric constant insulator film by irradiating the regions where the metallic patterns 214 for testing set by the metallic pattern coordinate setting process exist and the region of the low dielectric constant insulator film 213 with a laser beam under respectively different machining conditions.