To provide a method for an aeration treatment of sewage capable of sufficiently preventing the degradation in treatment efficiency of the sewage.

The method for the aeration treatment of the sewage which performs the aeration treatment of the sewage in a treating vessel 2 by using a plurality of air diffusion units 1a and 1b having diffusers 6 includes a process step of pulling up the unit 1a from the treating vessel 2 and of performing the aeration treatment of the sewage by the remaining unit 1b. According to the method, only the portion of the unit 1a is pulled up and therefore the time required for cleaning, maintenance, etc., of the air diffusers 6 in the unit 1a can be made shorter than in the case all of the units 1a and 1b are pulled up and the portion of the unit 1a can be rapidly returned into the sewage. In addition, the aeration treatment of the sewage is performed by the remaining unit 1b while the unit 1a is cleaned and therefore the aeration treatment of the sewage can be performed without interruption.