1. An information processing apparatus for managing attribute information as to resources constituting a system, comprising: an acquisition unit which obtains a plurality of attribute information as to the same resources; a degree of reliability calculation unit which calculates, when a contradiction exists between the plurality of attribute information obtained by the acquisition unit, a degree of reliability as to each of the plurality of attribute information; and an attribute information determination unit which sets the attribute information, which has the highest degree of reliability calculated by the degree of reliability calculation unit, as attribute information as to the resources.