A convenient environment flexibly coping with an environment in which an image forming apparatus capable of accepting a plurality of jobs is used can be constructed. For this purpose, in a job processing method of an image forming system including the image forming apparatus capable of accepting a plurality of jobs including a first job, print processing of the first job is performed by the image forming apparatus, and performance of print processing of a second job input after the first job can be prohibited based on checking information including at least any one of information associated with the first job subjected to the print processing and information associated with the second job although print processing of the second job can be performed by the image forming apparatus.