The present invention provides a plating pretreatment apparatus that includes a cylindrical cathode disposed in a hollow portion of a fixing jig. A cylindrical object to be treated is installed on the fixing jig so that the cathode is also arranged therein. A lower portion of the cathode has a smaller diameter than an upper portion thereof. The invention also provides a plating treatment apparatus that includes an outlet jig having a hollow portion for installing a cylindrical object to be treated on a top face thereof, a cylindrical anode disposed therein so that a top end thereof projects from the top face of the outlet jig, and a plating liquid tank connected to the anode and the outlet jig. A lower portion of the anode has a smaller diameter than an upper portion thereof.