A film loading method of an image forming apparatus, includes: loading an endless film which was stored in a container box, using at least two support members, to a film frame of the image forming apparatus, wherein the film is supported by the support members in a different form with respect to a condition of the film when loaded and fitted to the film frame. The support members are initially stored in the container box and serve as a packaging member for use in transporting and storing the film. The support members are attached to respective portions of the film frame and guide the film to be loaded and fitted onto the film frame. The film frame includes holding rollers, and the support members are attached to the respective portions of the film frame, coaxially with the holding rollers.