A hollow coated molded product is easily produced whose interior is coated, by using first and second moldings injection-molded through a first injecting step. Against first and second moldings injection-molded through a first injecting step, a coating device provided on a robot hand is butted and forms coatings thereon at a step at which a movable mold is separated from the fixed mold and thereafter, the first and second moldings are butted against each other and integrated through a second injecting step, whereby a coated molded product is formed.