Coaxial nozzle of laser beam machine

A coaxial nozzle of a laser beam machine comprising:

• an inner nozzle in which a laser beam and an inner gas pass through an inner side along an axial direction from a base end side to a tip end side of the inner nozzle, where the inner gas is ejected,
• an outer nozzle coaxial with the inner nozzle and surrounding an outer side of the inner nozzle such that a tubular shaped space between the inner nozzle and the outer nozzle is provided, an outer gas flows in the tubular shaped space and is ejected along the inner nozzle, and
• a cooling circuit provided around an outer circumferential wall of the inner nozzle, and having two longitudinal sections provided along the outer circumferential wall of the inner nozzle in the axial direction and a transverse section joining the longitudinal sections and partially surrounding the outer circumferential wall of the inner nozzle such that a cross jet gas flows from one of the longitudinal sections via the transverse section to another one of the longitudinal sections, for cooling an outer circumference of the inner nozzle, the cooling circuit defined by an inner circumferential wall of an intermediate tubular member and the outer circumferential wall of the inner nozzle, the intermediate tubular member being provided in the tubular shaped space between the inner nozzle and the outer nozzle and defines a portion of the tubular shaped space in which only the cross jet gas flows such that the flow of the inner gas and the outer gas is not disturbed, the cross jet gas flowing in the cooling circuit being distinct from the inner gas and from the outer gas and does not mix with the inner gas or with the outer gas.