A composite plating apparatus is disclosed in which an insertion electrode is loosely inserted into a hollow cylinder having a space, air bubbles are mixed into a composite plating solution fed from a liquid feeding pipe toward the space in the cylinder, and the hollow cylinder is connected to a base electrode so as to perform a composite plating on the inner surface of the hollow cylinder. An air bubble dispersing member having at least one passage hole with a diameter the same as or larger than a length of a gap defined between the insertion electrode and the inner surface of the cylinder is arranged upstream of a plating solution inlet portion of the hollow cylinder as an apparatus for dispersing air bubbles within the composite plating solution. The air bubble dispersing member can also be used as an electrode engaging member for engaging a tip end portion of the electrode inserted into the hollow cylinder.