A laser processing device includes a laser irradiation unit that performs processing on a workpiece by using a laser while scanning a workpiece surface to form a kerf, jet nozzles that respectively form jet flows flowing toward a bottom surface of the kerf on front and rear sides in a scanning direction of the laser, and an intake part that sucks, above injection ports of the jet nozzles, a gas in a region surrounded by the jet flows from the front and rear sides. In a state in which a certain region of the kerf is isolated by the jet flows, the gas is sucked from this region by the intake part. As a result, a suction force by the intake part can reach the bottom surface of the kerf.