Sesame oil is a simple pressed oil as unrefined oil. During manufacturing process of roasting-expression, benzo(a)pyrene[B(a)P] formed as a strong carcinogenic substance is cause a social problem. In manufacturing process of sesame oil, it had following the forming pathway of benzo(a)pyrene[B(a)P] as well as minimizing plan of B(a)P formation. Suitable roasting condition by roaster was during 15~20min at $220^{circ}C$, B(a)P content in sesame oil was $1.35{sim}1.57{mu}g/kg$. Between roasting temperature and/or roastingtime and forming amount of B(a)P was showed a linear correlation. As a point of view the turbidity and yield of final product, roasting process of the more regular level was required.