A secure, inexpensive, convenient 
payment system which allows an existing communication to be used to make an expensive 
payment terminal unnecessary, makes local communication unnecessary to make it possible to use the 
system by a seller and a buyer, uses closed-loop type 
electronic money to make it possible to make 
payment on delivery is obtained. An account 
database 6 which is arranged as equipment of a communication carrier and manages accounts of sellers and buyers (users), and a payment 
server 5 which is arranged as equipment of the communication carrier and performs an electronic payment process between the seller and the buyer are arranged. In the payment 
server 5, a primary payment 
server 3 and a secondary payment server 4 are arranged. When a payment request from a user is received through a communication network 10, the primary payment server 3 refers to the account 
database 6 to perform a real-time payment process by 
electronic money as primary payment between accounts of the seller and the buyer. Secondary payment is performed between the financial institution server 13 and the secondary payment server 4 in a predetermined period of time thereafter.