To provide a water treatment method and apparatus capable of enhancing the purifying capacity of water to be treated.

In a water treatment method for purifying water 1 to be treated by allowing fine particles of a photocatalyst 4 to be present in the water 1 to be treated in which a light emitting source 7 is immersed of a treatment tank 3 and irradiating the photocatalyst 4 with the light emitted from the light emitting source 7, suspended solids 5 to which the photocatalyst 4 is bonded are allowed to be present in the water 1 to be treated and gas is supplied to the water 1 to be treated to fluidize the water 1 to be treated and the suspended solid 5 and the water 1 to be treated is treated while the contamination of the light emitting source 7 is prevented. In this case, when the gas is supplied to the water 1 to be treated, the suspended solids 5 to which the photocatalyst 4 is bonded and the water 1 to be treated are fluidized and the adherend to the light emitting source 7 is effectively peeled by the collision of the suspended solids 5 and the light emitting source 7 is always held to a clean state. Therefore, the photocatalyst 4 is sufficiently irradiated with the light from the light emitting source 7 over a long period of time.