To provide an electrolytic plating method and apparatus therefor capable of depositing a dense plating film having a large film thickness on a plating base material with a small amount of plating liquid in a short time.

In the electrolytic plating method for depositing a plating film by metal ions in a plating liquid 1 on a plating base material 30, the plating treatment is performed in a state in which a path for diffusing gas generated during the plating treatment is formed separately from a plating film forming part. Concretely, a plating liquid keeping member 20 with a wound non-conductive liquid keeping material 22 with a space allowing a plating liquid 1 to be impregnated in a circumferential surface of a cylindrical electrode roller 21 charged to one pole is arranged with a part thereof entering the plating liquid 1, and a base material 30 charged to the other pole is brought into contact with the liquid keeping material 22. The plating treatment is thus performed.