To provide a delivery time reply method and its program for making a delivery time reply to a customer and a recording medium capable of performing sales promotion by improving a customer service by presenting a delivery time reply (guarantee value) in response to required information from the customer, and performing automatic security by utilizing the delivery time reply (guarantee value) at the time of legal order reception, and automatically erasing the guarantee value which does not lead to the legal order reception, and notifying the customer of the delivery time reply (guarantee value) in response to the required information of the customer.

This delivery time reply method and its program comprises a step for inputting required information corresponding to a product from a customer to a required information inputting means, a step for generating a temporarily secured guarantee value, and for replying to the customer in response to the inputted require information, a step for inputting the legal order reception information corresponding to the product from the customer to an order reception information inputting means, and a step for legally securing the guarantee value in response to the inputted legal order reception information.