An optimum auction method using a network is disclosed. Especially, being different from a typical auction method for simply evaluating a personally proposed bod price, the optimum auction method evaluates various evaluation particulars for the auction and evaluation methods in overall, thereby selecting an optimum bidder who is close to an intention or taste of an auction initiator or able to maximize a profit even though the selected optimum bidder does not propose the highest or the lowest bid price. Accordingly, it is also possible to broaden a range of participation and improve efficiency on the auction. Also, there are various types of the optimum auction method including a reverse auction, a lease auction and a reverse lease auction which can proceed with various trading methods by maximizing the profit of the auction initiator.