Laser processing apparatus and output power checking method

An output power checking method for checking, in a laser processing apparatus in which a laser beam emitted from a laser beam generation unit is branched at least to a first optical path and a second optical path by a branching unit and the branched laser beams are condensed to and irradiated upon a processing face of a workpiece held on a holding table by a condenser, output power of the branched laser beams, the output power checking method comprising:

• a total output power measurement step of measuring total output power of the laser beams at least of the first optical path and the second optical path emitted from the laser beam generation unit and condensed by the condenser;
• a blocking step of blocking at least the laser beam of the first optical path emitted from the laser beam generation unit and condensed by the condenser using a blocking member;
• a non-blocked laser beam output power measurement step of measuring output power of the laser beam, which is not blocked by the blocking member, in a state in which the blocking step is carried out;
• and
• a laser beam output power calculation step of calculating, based on the value measured at the total output power measurement step and the value measured at the non-blocked laser beam output power measurement step, first output power of the laser beam branched to the first optical path and second output power of the laser beam branched to the second optical path.