To provide a water purification method capable of reducing the number of pumps or ejectors to be installed for reducing equipment cost, moreover, changing the amount of powder active carbon to be added in accordance with drastic fluctuations of the necessary amount of powder active carbon to be added and reliably adsorbing odor components.

The powder active carbon is added to raw water by an active carbon supply device 2 and membrane filtration of the raw water is performed by a membrane module 3. A single active carbon supply device 1 having a liquid feed amount corresponding to the maximum odor concentration of the raw water is intermittently operated by a time in accordance with an odor concentration of the raw water. The powder active carbon is retained in the membrane module 3 and odor is adsorbed by the powder active carbon. A slurry pump or an ejector is used as the active carbon supply device 2.