This laser processing apparatus includes an irradiation unit and a controller. The irradiation unit has a spatial light modulator and a converging part. The controller executes first control for causing the laser light to be modulated by the spatial light modulator such that the laser light is branched into a plurality of rays of processing light and a plurality of converging points of the plurality of rays of processing light are positioned in different positions in a direction perpendicular to an irradiation direction of the laser light. In the first control, the laser light is modulated such that the modified region is present between a converging point of non-modulated light of the laser light and an opposite surface on a side opposite to a laser light incidence surface of the object in the irradiation direction.