To provide a laser beam machining device which reduces the diameter of a liquid column in the position of a workpiece and facilitates the control of alignment.

The laser beam machining device 1 includes: a spray nozzle 14 having a spray hole 14a; a liquid feeder 5 for pressure-feeding a liquid; a laser oscillator 4 for oscillating a laser light L; and a condenser 7 for condensing the laser light L oscillated from the oscillator 4. The liquid column C is formed by spraying a liquid fed from the liquid feeder 5 from the spray nozzle, and the workpiece 2 is processed by guiding the laser light condensed by the condenser using the liquid column. The laser beam machining device 1 further includes: a charged electrode 18 for electrizing the liquid sprayed from the spray nozzle 14; and an attraction electrode 19, provided between the spray nozzle and the workpiece, for acting on the liquid column C comprising a charged liquid to reduce the diameter of the liquid column C.