This paper proposes the first sealed-bid auction method which uses only hash function. We use a hash chain to commit a bidding price. By using the hash chain, we can drastically reduce the time needed for bidding and opening bids. If we use a practical hash function e.g. SHA-1, our method is 200,000 times faster than former methods that use public key cryptosystems. Accordingly, our method is capable of wide application in terms of the number of bidders and the range of bidding prices.