Recently, security of the computer systems becomes an important problem. Almost all computers use the password mechanism for the user authentication. But password mechanism has many issues. In this paper, we propose a kind of biometrics authentication method using the timings of key strokes of an identical simple phrase for all users. For this method, selection of the phrase is important. We analyzed the timings of key strokes using Self Organizing Map (SOM) and selected the suitable phrase for authentication. We examined the effectiveness of this method with the authentication experiments using the map organized by SOM.