To provide a personal identification system and method for surely executing personal identification by supplementing the security of an identification system using only a code such as a password or supplementing the inaccuracy of the identification system based on biological information under the consideration of the improvement of the convenience of a user in a transaction system such as on-line banking.

This invention is provided to execute personal identification based on the combination of the optimal identification methods according to users and transaction classifications or the like. An identification rule data base 21 is registered with the combination of the identification methods or the order of identification for each account and transaction. An identification information data base 22 is registered with identification data corresponding to the respective identification methods. When an identification information accepting part 25 has received the identification data inputted to a customer terminal 40, an identification information deciding part collates the identification information data base 22 or the like, and executes personal identification according to the rule registered in the identification rule data base 22.