To decrease the number of exchange times of protective glass by preventing the adhesion of spatters on a protective glass particularly when processing by laser welding is executed.

This laser beam processing head 1 condenses a laser beam LB with a condenser lens 5 disposed therein and irradiates a work W to be worked with the condensed laser beam LB from a laser nozzle 7 disposed at its front end. The head described above is internally provided with a protective lens 9 inclined with the optical axis C of the laser beam LB between the condenser lens 5 and the laser nozzle 7. The head is otherwise provided with the protective glass 9 rotatable or oscillatable in a horizontal state orthogonal with the optical axis C of the laser beam LB.