A wafer processing device, according to one embodiment of the present invention, may comprise: a laser generation part which generates a beam for processing a wafer; a slot part which has inserted therein at least one diffractive optical element for splitting the beam into a plurality of beams, and which comprises a plurality of slots formed so as to enable the beams to pass therethrough; and a scanner which transfers the beams transferred from the slot part to the surface of the wafer.