An image forming apparatus is provided. The image forming apparatus includes a storage unit which stores information regarding the other image forming apparatuses of the same group as the image forming apparatus and quota information of each user which is shared by the other image forming apparatuses, a controller which, if a job command is input, determines whether to perform a job according to whether the number of copies requested by the job command satisfies the quota information of each user, a function unit which performs the job under control of the controller, a quota information administration unit which updates the quota information of each user stored in the storage unit as the job is performed, and a communication interface which transmits the updated quota information of each user to the other image forming apparatuses.