A laser processing apparatus including a processing nozzle for irradiating a workpiece with laser beam, a driving mechanism for relatively moving the processing nozzle and the workpiece, and a gap sensor for detecting a gap between the processing nozzle and the workpiece. The apparatus includes a gap control section referring to a measured value detected by the gap sensor and calculating a manipulating variable used for controlling the driving mechanism so as to maintain the gap during execution of laser processing at a first dimension, a power monitoring section monitoring electric power from a power supply and sending an abnormality detection signal to the gap control section when a power abnormality occurs, and a control action switching section switching a control action of the gap control section so as to increase the gap from the first dimension when the abnormality detection signal is sent to the gap control section.