The purpose of this study is to propose an evaluation method of ARAS (Advanced Rider Assistance System). Many studies focused on accident-reduction effects, but few studies evaluate the balance between cost and benefit. Such researches can be used to investigate which system is better to be introduced to the market. In this study, we quantified the social usefulness of ARAS by using insurance data to convert the benefit due to the introduction of ARAS into money. We combined RS (Riding Simulator) experiments and computer simulation based on time-series reliability model and integrated error model for cost-benefit analysis. In our suggested cost-benefit analysis, we compared the reduction of human and material loss due to the introduction of ARAS as a social benefit with the cost required for the introduction of ARAS as a social cost. We can investigate whether ARAS is useful from the cost-benefit ratio. As a result, under the assumed conditions in this study, if the ARAS price is set at JPY 10,000, JPY 30,000, JPY 50,000, and JPY 70,000, the cost-benefit ratio for the tenth year will be 4.98, 1.66, 1.00, 0.71, respectively. We confirmed that we can evaluate social usefulness of ARAS using cost-benefit analysis.