A laser processing device in which even a short nozzle provided with a follower roller (35) can prevent disturbance of a laser beam and contamination of protective glass and in which shield gas can act effectively. The laser processing device comprises a head section (11) from which a laser beam that is condensed by a condenser lens (16) provided inside the device is irradiated through a nozzle section (13); a gas delivery means (28) opened in a processing direction X, in the vicinity of the focal point of laser beam, and jetting a shield gas from the opening; a primary air delivery means (31) directed in the processing direction X, above the focal point F of the laser beam, and jetting primary air A1 substantially in the horizontal direction to form a first air curtain; and secondary air delivery means (18, 13, 19) directed to the focal point from the vicinity of the condenser lens and jetting secondary air A2 to form a second air curtain.