The present invention provides a confidential information management system which allows users to securely obtain confidential information files containing various confidential information, which files are securely stored in the present system, anywhere and anytime, using a minimum of confidential information. A confidential information file and encoding/decoding software are downloaded to an information terminal from a confidential information managing server and an encoding/decoding software managing server, respectively, so that the confidential information file is decoded on the information terminal by using the encoding/decoding software. The present system is applicable to various (computer) systems which store and manage confidential information (ID numbers, passwords, encryption keys, digital certificates, etc.) for use in user verification.