An oral cavity cleaner according to an exemplary embodiment of the present disclosure includes: a handle including an inflow path through which washing water flows and a discharge flow path through which contaminated water sucked from an oral cavity flows; a mouthpiece connected to the inflow path and configured to spray the washing water into the oral cavity; a core suction part configured to suck the contaminated water that has been discharged from the mouthpiece and washed teeth; and a suction pipe in which the contaminated water flows, the suction pipe being disposed in the mouthpiece and configured to connect the core suction part and the handle.