1. A management policy evaluation system constituted by a computer for evaluating a management policy that establishes a rule for assigning an IT resource to be provided in a system that offers service to a user, in accordance with a state of use by the user, the evaluation system comprising: a demand recording part for recording demand data representing a change in a value of a demand for the service from the user in a predetermined period, the value of the demand being expressed as an operating amount of the IT resource; a supply recording part for recording supply data representing a change in a value of a supply of the service to be provided by the IT resource to be assigned based on the management policy in the predetermined period, the value of the supply being expressed as the operating amount; a calculation part for comparing the demand data recorded in the demand recording part with the supply data recorded in the supply recording part, so as to calculate shortage/surplus data representing a change in shortage/surplus of the IT resource with respect to the demand in the predetermined period; and an evaluation part for generating evaluation data representing a loss or a profit to be created when the IT resource is assigned based on the management policy in the predetermined period, by using the shortage/surplus data calculated by the calculation part.