To provide a mediation system capable of properly reflecting a transacting relation with a provider at the time of selecting the provider to transact with.

An input means 12 receives identification information specifying commodity from a transaction requesting person, an extracting means 13 extracts a provider providing commodity specified by received identification information from an information with the correspondence of the commodity information holding means 11 and a selecting means 15 selects a provider transacting probability corresponding to an evaluated value held in an provider information holding means 11 from in plural extracted providers. Consequently, at the time of selecting a provider to transact with, the evaluated value concerning transaction is properly reflected.