A laser processing device having a function for avoiding interference during an approach motion of a processing nozzle of the laser processing device. When a distance between a processing nozzle and a workpiece is equal to a setting value where gap control can be started, it is judged as to whether or not the mechanical position of the processing nozzle is above a predetermined processing start position. When the mechanical position of the processing nozzle is higher than the processing start position, a controller judges that an abnormality occurs by which laser processing cannot be carried out, and automatically stops the approach motion of the processing nozzle.