An image processing apparatus includes a request determining unit receiving an operation event indicating a request to use an image processing function and determining whether the request is from a guest user based on the received operation event; a guest login processing unit generating guest login information including a guest user identifier and access right information of the guest user if the request is from the guest user and sending a login request to request a login process for the guest user based on the guest login information; an access control unit disabling access control on the image processing function in response to the login request based on the access right information in the guest login information; and a usage history recording unit recording a usage history of the image processing function in association with the guest user based on the guest user identifier in the guest login information.