This study evaluated economic feasibility to find a method that can increase income of a rape farmer for biodiesel. Biodiesel is one of an important bioenergy that can be used to substitute diesel-fuel. A rape is useful not only for biodiesel, but also for a substitute of a barley. This study deals with the income and cost data of a rape farmer compare to that of a barley farmer. According to the result of economic evaluation from 2002 to 2006, the income of a rape farmer for biodeisel incurred a loss. However, this study showed that the income of a rape farmer would be approximately 80% of that of a barley farmer if a new variety of rape called ‘SUNMANG’ was growed. Also, biodiesel has various ancillary effects such as by-product, preservation of a scenery, reduction of CO2, etc. If the income of a rape farmer had ancillary effects, it would exceed the income of a barley farmer. As a result, we need to support ancillary effects of a rape to encourage a rape farmer for biodiesel.