1. An information management method for use in an information management system that collects, from at least one of target appliances, log information regarding the at least one of target appliances via a home gateway and manages the log information, the method comprising: receiving an appliance identifier of an unregistered target appliance among the at least one of target appliances, a gateway identifier of the home gateway, and biological information regarding a user of the unregistered target appliance; determining whether among the registered appliances associated with the gateway identifier, management information regarding at least one of the target appliances associated with the user of the biological information is registered in a database; registering, if it is determined that the management information regarding at least one of the target appliances associated with the user of the biological information is registered in the database, the management information regarding the at least one of the registered target appliances in the database as management information of the unregistered target appliance in association with the user of the biological information; and sending, to an information terminal of the user, display information indicating that the management information regarding the at least one of the registered target appliances is registered as management information of the unregistered target appliance in association with the user of the biological information, wherein at least one of the receiving, the determining, registering and the sending is performed by circuitry.