An information management system includes: an attribute information DB that stores attribute information of a user as user information; a data obtainer that obtains, from at least one home appliance used by the user, first device data including an operating status of the at least one home appliance; and an updater that updates the user information stored in the attribute information DB, using first attribute information that is based on the first device data obtained. The updater compares the first attribute information and second attribute information stored in the attribute information DB as the user information to determine whether a difference is present between the first attribute information and the second attribute information, and updates the user information with the first attribute information when determining that the difference is present, and does not update the user information when determining that no difference is present.