Laser apparatus including plurality of laser modules

A laser apparatus comprising:

• a plurality of laser modules;
• a laser power source section configured to drive each of the plurality of laser modules;
• a combiner configured to combine laser beams emitted by the plurality of laser modules, and to output a combined laser beam;
• an optical output command section configured to generate a first optical output command with respect to the combined laser beam;
• a laser module selection/command section configured to select a laser module to be driven from the plurality of laser modules, based on the first optical output command, and to generate a second optical output command for each of the plurality of laser modules;
• and
• a control section configured to control the plurality of laser modules and the laser power source section, based on the second optical output command,
• wherein, when changing the number of laser-oscillating laser modules in accordance with a change in the first optical output command, the laser module selection/command section outputs the second optical output command, in a period from when the number is changed to when a predetermined period of time elapses, to at least one of the plurality of laser modules that has been laser-oscillating before the number is changed, such that the combined laser beam having an output corresponding to the first optical output command is outputted only by the at least one of the plurality of laser modules that has been laser-oscillating before the number is changed.