According to an embodiment of the present invention, a method for providing a loan service includes the steps of : receiving a subscription request to a certain real estate related loan product from a loan applicant; receiving a loan document of the loan applicant from a loan document providing server and authenticating whether to allow a loan of the loan applicant using the loan document of the loan applicant; providing a loan service for at least one of a down payment, a middle payment, and a balance which are supported by the certain real estate related loan product according to authentication results of the loan applicant; and redeeming a loan for at least one of the down payment, the middle payment, and the balance using a mileage associated with the loan applicant if a redeeming request for the loan for at least one of the down payment, the middle payment, and the balance is received from the loan applicant. According to the method of the present invention, the loan document providing server provides the loan document of the loan applicant, thereby providing the loan applicant with the loan service through the authentication process of the loan applicant without visiting a bank in person with the loan document.