Provided is a low-cost, highly active, environmentally friendly living radical polymerization catalyst which does not require a radical initiator. An organic compound having an oxidation-reduction capability is used as a catalyst. Even if a radical initiator is not used, a monomer can be subjected to a radical polymerization to obtain a polymer having narrow molecular weight distribution. The cost of the living radical polymerization can be remarkably reduced. It is made possible to prevent adverse effects of using a radical initiator. The present invention is significantly more environmentally friendly and economically excellent than conventional living radical polymerization methods, due to advantages of the catalyst such as low toxicity of the catalyst, low amount of the catalyst necessary, high solubility of the catalyst, mild reaction conditions, and no coloration/no odor (which do not require a post-treatment for a molded article), etc.