To provide a removing agent capable of easily and safely removing in a short time an organic silicon coating layer and/or an oxide coating layer provided on a base material made of a resin, to provide a recovering and regenerating method of the base material made of the resin using the removing agent, and to provide a manufacturing method of an article having the coating layer using the regenerated base material.

The removing agent for the organic silicon-based coating layer and/or the oxide coating layer comprises a hydrogen fluoride compound and a surfactant. The regenerating method for the base material comprises dipping article having the organic silicon-based coating layer, the oxide coating layer, or the organic silicon-based coating layer and the oxide coating layer on the base material in an aqueous solution containing the hydrogen fluoride compound and the surfactant and removing at least a part or the whole of the coating layer. The manufacturing method of the article having the coating layer comprises providing the organic silicon-based coating layer, the oxide coating layer, or the organic silicon coating layer and the oxide coating layer on the base material regenerated by the regenerating method.