A laser beam machine can make quality of machining almost constant in such a manner that a first reflecting means in a first beam guide portion is moved and driven so as to maintain a length of an optical path of laser beam to be almost constant in spite of a moved position of a machining head. In a first embodiment, light is transmitted into an optical 3 dB coupler, and split into a transmission down a first optical fiber and transmission down a second, significantly longer second optical fiber. In a web server, the inputoutput capacity may be the resource to be maximized.