1. An electronic-program-guide retrieval method comprising the steps of: when retrieval based on an input retrieval keyword is performed by accessing an electronic-program-guide database storing electronic-program-guide data, extracting relevant-keyword information relevant to said input retrieval keyword from a dictionary database; and extracting necessary electronic-program-guide data based on the extracted relevant-keyword information from the electronic-program-guide data stored in said electronic-program-guide database.