To grasp the setting order of a plurality of documents in an automatic document feeding unit, and to properly create a booklet with ring binders desired by the user.

An image forming system including an image forming apparatus IF and a ring bookbinding device RG is configured to manufacture the booklet with ring binders. In the manufacturing of the booklet with ring binders by setting the plurality of documents in the automatic document feeder ADF and using the sheets on which the document images are formed, a screen set by the user is displayed on an operation display part OP regarding the setting order of the documents including a document corresponding to the cover sheet of the ring-bond booklet in the automatic document feeder ADF, and then, the booklet with ring binders is manufactured on the basis of the setting order of the documents selected by the user.