To provide a method for calculating on real-time the satisfaction ratio on delivery sales-requested date capable of confirming a delivery date satisfaction ratio in a real time.

A sales staff calculates a date of delivery by a date of delivery answer calculation logic from a requested date of delivery and a possible delivery date to merchandise obtained, by summing up orders inputted from a user to an order receiving terminal 20 according to the business with the user, and transmits the date of delivery answer information to the order receiving terminal 20. This date of delivery answer information is held in a date of delivery answer data base 60, and the tight situation of the merchandise is calculated from the date of delivery answer information by a delivery date satisfaction ratio calculating tool 702, and carried in a delivery date satisfaction ratio web 80 opened over the Internet by a factory. Then, the sales staff performs processing for acquiring materials for the merchandise by confirming the tight situation by a sales terminal 10.