A laser beam irradiating unit of a laser processing apparatus includes a laser oscillator, a mirror configured to reflect a laser beam emitted from the laser oscillator and propagate the laser beam to a processing point, a power measuring unit configured to measure power of leakage light of the laser beam transmitted without being reflected by the mirror, and a condensing lens configured to condense the laser beam propagated by the mirror and irradiate a workpiece with the condensed laser beam. The control unit measures the power of the leakage light of the laser beam by the power measuring unit while irradiating the workpiece with the laser beam.

A laser beam irradiating unit of a laser processing apparatus includes a laser oscillator, a mirror configured to reflect a laser beam emitted from the laser oscillator and propagate the laser beam to a processing point, a power measuring unit configured to measure power of leakage light of the laser beam transmitted without being reflected by the mirror, and a condensing lens configured to condense the laser beam propagated by the mirror and irradiate a workpiece with the condensed laser beam. The control unit measures the power of the leakage light of the laser beam by the power measuring unit while irradiating the workpiece with the laser beam.