PROBLEM TO BE SOLVED : To provide an electronic real estate transaction method that can simultaneously satisfy respective demands of a person who is economically anxious about retirement despite the possession of real estate such as a dwelling house and of a person who thinks to purchase desirable real estate on a satisfactory condition.SOLUTION : According to the indication of a seller who wants to sell real estate, a seller terminal device 2 offers a center terminal device 1 the selling of the real estate (S1). The center terminal device 1 posts the offer through a communication network to hold an auction (S2). According to the indication of a buyer who wants to purchase the real estate up for the auction, a buyer terminal device 3 offers a bid presenting a purchase condition to the center terminal device 1 (S3, S5, S7). The center terminal device 1 awards the bid presenting the most advantageous purchase condition to the seller out of two or more of those offered by buyers at the auction (S9 to S11).