PURPOSE: To apply coating liquid on a drum outer peripheral face continuously by storing the coating liquid overflowing from a coating tank in a subtank, imparting a predetermined viscosity to the liquid, and then feeding the same into an agitation tank and returning the liquid from the agitation tank to the coating tank.

CONSTITUTION: A drum 70 for applying coating liquid to the outer peripheral face is immersed in a coating tank 10 in the state that its coating liquid overflows. Also, the overflowing coating liquid out of the coating tank 10 is stored in a subtank 30, and the coating liquid is replenished properly. Further, the viscosity of coating liquid in the subtank 30 is automatically adjusted by an automatic viscosity adjusting device 61. The coating liquid fed from the subtank 30 is stored and agitated in an agitation tank 53, and also the stored coating liquid is fed into the coating tank 10. As a result, the coating liquid can be applied on the outer peripheral face of the drum by the given thickness, and also the coating work of the drum can be performed continuously.