A service provision apparatus and related method which provides a service for a user via a network includes a setting unit, a determination unit, and a decision unit. The setting unit sets an evaluation policy for evaluating reliability of at least one authentication apparatus performing authentication on the user. The determination unit determines whether the authentication made by the at least one authentication apparatus is to be relied on, on the basis of at least one evaluation result obtained by evaluating whether the at least one authentication apparatus is to be relied on, on the basis of the evaluation policy. The decision unit determines that the service is to be provided for the user in response to a determination that the authentication made by the at least one authentication apparatus is to be relied on and information that the user has been authenticated by the at least one authentication apparatus.