To provide a contract apparatus by which verification time in a contract is shortened and the contract with an applicant who has tried to conclude an illegal transaction contract in the past is prevented, and to provide an authentication biological information retaining apparatus and a database constructing method.

The authentication biological information retaining apparatus is connected, through a communication network, to the contract apparatus performing identification of an applicant wishing a transaction with a financial institution, and acquiring biological information from the applicant, and stores the authentication biological information to be referred to for transaction examination on the basis of the acquired biological information. In the database constructing method in the authentication biological information retaining apparatus, the storing authentication biological information is the biological information on a person targeted for application rejection and the biological information acquired prior to the identification is stored as the authentication biological information when a problem has arisen in the authentication. Consequently, the omission of examination for the applicant is prevented.