This study is carried out to compare the quality of sesamin oil using to 52 restaurants in city with that of pure sesamin oil. The pure sesamin, corn soybean and perilla oils used reference oil commodities of famous corporations. The fatty acid, sesamin and sterols of reference and restaurant oils are analyzed by gas chromatography. The results are as follows; 1. A pure sesamin oil can be identified with the component and content of fatty acid, sterol and sesamin. 2. In 52 restaurant oils, 12 oils (23％) are estimated as pure sesamin oil and the remainders (77％) are mixed with corn oil, soybean oil an perilla oil. 3. The sesamin oil that is mixed with corn oil is 35％, soybean oil is 17％ and perilla oil is 15％.