1. A document searching method for multilingual documents comprising the steps of: inputting a search command including a search key word designated by a searcher; translating the key word designated by the searcher into another language used in the documents to be searched; generating a search formula from the translated key words; searching documents according to the search formula; storing selected documents as a search result; and translating the selected documents stored in said step of storing, wherein said step of translating the selected documents includes translating into the language designated in said step of inputting a search command.