To enhance the convenience of a bookmark function for web pages, a system for displaying identification information enables a user to select a file. Included is a storage section that stores identification information of each of classified files in association with tag information indicating classification of contents of that file, a search section that, in response to inputting of tag information to be registered, searches the classified files for a file including information matching with the input tag information, a first storing section that stores the input tag information in the storage section in association with identification information of the searched file, and a display section that, in response to a display request for identification information designating tag information, reads identification information associated with the designated tag information from the storage section, and displays the read identification information.