The second price auction is an auction method in which the person who bids the highest bid when all the participants bid at the same time buys the bid at the second highest bid price. There is a problem that financial fairness, which is the financial guarantee for parties that perform proper behavior, cannot be satisfied at the same time. This paper proposes an efficient second-price auction protocol that guarantees financial fairness by introducing a smart contract, can hide the information from the administrator, and can verify its validity without using a reliable institution.