Laser machining head and laser machine

A laser machining head comprising:

• a first lens group to which laser light diverging from a light emitter enters and configured to concentrate the laser light, wherein the first lens group is a lens group having positive power;
• a second lens group to which the laser light having passed through the first lens group propagates, wherein the second lens group is a lens group having positive power;
• a third lens group, wherein the laser light having passed through the second lens group propagates to the third lens group, and wherein the third lens group is a lens group having negative power;
• a fourth lens group to which the laser light having passed through the third lens group enters and configured to concentrate the laser light, wherein the fourth lens group is a lens group having positive power;
• a light flux conversion optical element removably disposed on an optical axis between the first lens group and the second lens group and configured to convert a beam mode of the laser light into a ring-shaped beam mode at a transfer position, the light flux conversion optical element being a single axicon lens;
• a first mover configured to move the first lens group in an optical axis direction;
• and
• a second mover configured to move the third lens group in the optical axis direction,
• wherein the first lens group, the second lens group, the third lens group, and the fourth lens group constitute a transfer optical system which forms an image of the light emitter at the transfer position, and
• wherein, when the light flux conversion optical element exists on the optical axis, the light flux conversion optical element is also included in the components of the transfer optical system.