In Kyushu University, a traditional "Student ID" based on student number assigned by Student Affairs Department had been used as the user ID of various IT services for a long time. There were some security and usability concerns using Student ID as a user ID. Since Student ID was used as the e-mail address of the student, it was easy to leak outside. Student ID is constructed based on a department code and a serial number, so guessing other ID strings from one ID is easy. Student ID is issued at the day of the entrance ceremony, so it is not usable for pre-entrance education. Student ID will change when the student moves to another department or proceeds from undergraduate to graduate school, so he/she loses personal data when Student ID changes. To solve these problems, Kyushu University decided to introduce another unchanging user ID independent from Student ID. This paper reports the design of new user ID, ID management system we are using, and the effect of introduction of new user ID.