An image processing system includes an image processing device executing a job and a billing server performing billing process in response to execution of the job connected through a network. The billing server includes: a remaining amount management part for managing a remaining amount of each user's available funds; and a savings amount transmission part for determining a savings amount in the image processing device based on a user's available funds and sending the determined savings amount to the image processing device. The image processing device includes: a savings amount storage part for storing therein the savings amount in accordance with the user; a job execution part for executing a job with an instruction by the user; and a billing processing part for performing billing process to charge to the user in response to execution of the job.