An image forming system has an image forming apparatus which has a printing unit which can perform a printing process of data of a storage unit which can store data of a plurality of jobs and which has a conveying unit which can convey a sheet from the print unit to a sheet processing device which can perform sheet processing, including at least a gluing process, for sheets from the printing unit, the system comprising: a controller adapted to permit a predetermined process related to the gluing process when the job to be processed is a job which meets a predetermined condition, and to inhibit the predetermined process related to the gluing process when the job to be processed is not a job which meets the predetermined condition, thereby overcoming obstacles to realization of an image forming system capable of a gluing process.