A laser machining device capable of recovering an exhaust performance of a dry pump easily is provided. A laser machining device includes: an oscillating portion that generates a machining laser beam G; an enclosure portion in which a first gas is enclosed; and an exhausting portion that exhausts the first gas together with a dirt generated in the enclosure portion in association with an operation of the oscillating portion. The exhausting portion includes: a dry pump; a first line that connects the enclosure portion and the dry pump; a second line that supplies a second gas having a higher pressure than the first gas to the dry pump; a valve portion that opens or closes the first line and the second line; and a control unit that controls opening or closing of the valve portion.