An image processing apparatus for providing at least a service to a service requestor receives a service execution request and authentication information of a service requestor from the service requestor and issues a request for authenticating the service requestor to an authentication service. Also, the image processing apparatus executes the requested service based on an authentication result transmitted from the authentication service. Further, the image processing apparatus manages an execution state of the executed service and an authentication state of the service requestor by associating the execution state with the authentication state.