A laser system having an automatic diagnosis function enabling a plurality of laser diodes to be diagnosed for faults in a short time.The laser system includes a judging part judging the presence of a fault or deterioration of a component of the laser system. The judging part is configured to judge the presence of a fault or deterioration of a component of the laser system based on the results of detection of a first photodetection part and second photodetection part when successively driving a plurality of laser diode module groups included in an individual laser oscillation unit so that the mutual drive times do not overlap simultaneously for at least two laser oscillation units among a plurality of laser oscillation units.