The present invention provides a password recovery system that re-supplies a password to only the legitimate user of the password. The password recovery system includes a memory card with CPU and a mobile phone. When a password needs to be recovered, a phone call is made, to the mobile phone, from a telephone connected to a phone line whose phone number is registered in advance into the memory card with CPU. The mobile phone then obtains the telephone number of the phone line via a caller's telephone number notifying service. It is judged whether the obtained telephone number and the registered phone number are the same, and when they are the same, the password stored in the memory card with CPU will be re-supplied so that the user can recover it.