Laser machining method and laser machining device

A laser machining device comprising:

• a plurality of laser emitting ends arranged separately from each other to emit a beam of laser light, respectively, in a form of pulse into a space;
• a light collection optical system on which beams of the laser light emitted from the plurality of laser emitting ends are incident, the light collection optical system being configured to reduce a gap between the beams of the laser light to such an extent that a plurality of the beams of the laser light are prevented from intersecting each other on a surface to be machined;
• and
• a driving mechanism to move the light collection optical system and the surface to be machined relative to each other both along the surface to be machined and in a second direction orthogonal to a first direction, wherein
• the laser machining device is controlled to move the light collection optical system and the surface to be machined relative to each other by the driving mechanism to simultaneously form a plurality of grooves on the surface to be machined while irradiating the surface to be machined with the plurality of the beams of the laser light emitted from the light collection optical system to form a plurality of focused spots separated from each other in the first direction.