The invention provides a molding apparatus capable of obtaining a reference mark utilizing characteristics of molding of a polarizing film in the course of molding the polarizing film, and adapted for large items small scale production of the polarizing film. The molding apparatus is made up of a molding box which is opened at an upper face, a closing valve attached to a suction port communicating with an inner space of the molding box, a vacuum source connected to the closing valve, pressing means provided at an opening edge of the molding box, and a mold having a concave spherical molding face and installed in the molding box, allowing the polarizing film to be sucked onto the molding face by vacuum suction to mold a colored concave and convex polarizing film. In the course of molding the concave and convex polarizing film by allowing the polarizing film to be sucked onto the convex spherical molding face by vacuum suction, the polarizing film is differentiated in stretching and is partially deep in color, thereby forming reference marks.