An oral cavity washing device includes a nozzle and a pump that supplies a liquid to the nozzle. The nozzle has a nozzle flow passage and a reduced part that is disposed in an intermediate part of the nozzle flow passage and that is smaller in cross-sectional area than a rest of the nozzle flow passage. A first flow passage and a second flow passage that are in parallel to each other are disposed between the nozzle and the pump. The first flow passage has a first valve that causes the first flow passage to be opened only when the pump sucks the liquid. The second flow passage has a second valve that causes the second flow passage to be opened only during discharge performed by the pump.
