Laser processing machine

A laser processing machine comprising:

• a plurality of collimating lenses which convert a laser beam from a laser oscillator into parallel rays of light, the laser beam emerging from a point of emergence of a transmission optical fiber, the plurality of collimating lenses being spaced from each other in an orthogonal direction perpendicular to an optical axis;
• a condensing lens operable to collect the laser beam, which has been converted into the parallel rays of light, and then to radiate the collected laser beam onto a work to be processed;
• a nozzle positioned on one side of the work adjacent the condensing lens and operable to discharge an assist gas, a distance from the point of emergence to a tip of the nozzle being unchangeable;
• and
• a switching device which switches a position of the plurality of collimating lenses in the orthogonal direction so that an arbitrarily chosen one of the plurality of the collimating lenses may have a lens center thereof coinciding with the center of the laser beam emitted from the point of emergence,
• wherein the plurality of the collimating lenses have respective focal lengths that are different from each other.