Abstract: A service provision system provides a predetermined service to a user and includes a server unit configured to provide a service and an authentication server unit configured to determine whether the user is an authorized user, wherein the server unit includes a service provision means that provides information about the user to the authentication server unit and executes provision of the service to the user who is determined as an authorized user and a transmission means that transmits information about an operation performed by the user on the server unit to a verification device, wherein the authentication server unit includes a determination means that determines whether the user is an authorized user based on information about the user and a reception means that receives an index indicating that the user is not an authorized user from the verification device.