According to the Super career development theory, high school students as adolescents need to have a clear understanding of their career orientation. Career orientation is defined as the direction of the tendency to make conclusions about future career expectation. The phenomenon is not easy to reveal students' career orientation due to the limitations of measuring instruments used by school counselors. Using Rasch analysis model, this study aims to measure the psychometric properties of 20 items on the Career Orientation Scale (COS), including measuring the validity and reliability of this scale which is specially prepared for high school students. The study involved 65 high school students who were taken by random sampling. The results showed that COS had psychometric properties and internal consistency so that it proved to be a valid and reliable research instrument. This research implies that COS can be used by researchers to collect data or information related to the career orientation of high school students.