1. An image processing apparatus for creating an electronic file from a paper document with the use of an optical reading device, comprising: a detecting part detecting a code included in image data read by means of the optical reading device; a data creating part decoding said code to obtain identification information, obtaining related information identified by said identification information, and obtaining character information from said related information, and creating character data from said character information; and a file creating part creating a document file storing said character data, wherein said character data is stored in a text layer when said document file comprises the text layer and an image layer.