The present invention provides a surface treatment apparatus for molded polymer products. In the operation, a molded polymer product is held by a jig (11) on a product loading and discharging unit (20) and is fed by a product feeding unit (10). A first impurity removing unit (30) cleans the surface of the product. The product passes through an inlet vacuum unit (40) and reaches a product surface ion treatment unit. The ion treatment unit controls an ion beam electric current and produces plasma cations using gas supplied from an atmospheric gas supply unit (60), and the plasma ions are evenly scanned onto the product surfaces. The surface-treated molded product passes through a second impurity removing unit and is fed to the product loading and discharging unit, at which the jig exchanges the existing product for a new product.