To prevent bubble preventive effect from being degraded without causing the oscillation of a float and the turbulence of a coating material even when coating is repeated in the case of dip-coating a cylindrical base body by using the float.

In this method the cylindrical base body 1 whose upper end is closed and whose lower end is opened is vertically dipped into the coating material 6 to coat it with it, a float having an outer diameter smaller than an inside diameter of the cylindrical body 1 and supported movably in the up and down directions so that it is positioned in the center of a coating tank 7 by a bar 4 vertically erected is floated on the surface of the coating material, and the cylindrical body 1 is dipped so that the float 3 is put in the inside of the cylindrical body 1. As the cylindrical base body, a base body for a photoreceptor drum or a base body for a developing sleeve is exemplified.