There are at least four patterns of mounting the original on which an original image including a predetermined image marking “SECRET” indicating the content is confidential information, in an original mounting unit such as an ADF. The image processing apparatus generates image data expressing the image depending on the original mounted state, and four pattern images are obtained depending on the direction of mounting the original. Of the plural original mounted states corresponding to plural layout states such as position or direction of the predetermined image, the predetermined mounted state of the original permitting image processing is preliminarily noticed to an authorized user, and image processing is prohibited when the layout state of the predetermined image corresponding to other mounted state than the predetermined mounted state is given, so that image processing by unauthorized user can be prevented.