A shop side terminal (2) generates first transaction identification information indicative of the content of a transaction corresponding to a financial service designated by a user and transmits that information to a settling server unit (3) of financial service designated by the user. A mobile communication terminal (1) generates second transaction identification information indicative of the content of the transaction based on information inputted by the user and transmits that information to the settling server unit (3) of financial service designated by the user. The settling server unit (3) receives the first transaction identification information from the shop side terminal (2) and the second transaction identification information from the mobile communication terminal (1) and settles an account for the transaction only when the content of first transaction identification information matches the content of second transaction identification information.
