When rice bran is stored for a long time, the free fatty acid (FFA) concentration in rice bran oil increases; hence, it is difficult to use the oil as a fuel for diesel engines. This study aimed to promote electrification using biofuel derived from rice bran oil; in order to use rice bran oil as a fuel, it is necessary to control the increase in the FFA concentrations. A low-cost and simple treatment of preserving rice bran that also considers the safety of defatted rice bran intended for consumption was investigated and the heat treatment method was selected. Milled rice bran was treated at 100℃ for 1 h and stored at 30℃ for 6 months; the FFA concentration in the rice bran oil was suppressed to approximately 10%. At this concentration, FFAs do not notably corrode engine components and affect oil viscosity; therefore, rice bran oil can be used as a fuel. Although there is no noticeable difference between the properties of Japanese rice and the New Rice for Africa (NERICA), we confirmed that the same effect could be achieved in NERICA. Overall, heat treatment effectively inhibited rice bran deterioration during storage, by suppressing the increase in FFA concentration in the oil and reducing oxidative damage.