A workflow system which restricts improper operations on an object circulated in a workflow by dynamically modifying access rights for the object according to the working status of the workflow. For example, the workflow system is a system which processes an object according to a workflow having a plurality of working statuses. When the working status for the object is changed, a modifying unit modifies access rights applied to the object. A control unit then controls operations on the object based on the modified access rights.