A laser processing device converges laser light at an object to be processed so as to form a modified region within the object along a line to cut. The laser processing device comprises a laser light source emitting the laser light, a spatial light modulator modulating the laser light emitted from the laser light source, and a converging optical system converging the laser light modulated by the spatial light modulator at the object. The spatial light modulator displays an axicon lens pattern as a modulation pattern so as to form converging points at a plurality of positions juxtaposed close to each other along a laser light irradiation direction.