There are many small islands in the Seto-Inland Sea. The depopulation and population ageing of these islands have caused steady decrease in the users of passenger boat lines which connect between these islands and the mainland. Because of this, some of the lines have been on the verge of closing their services and some of them are already given subsidy from the local government in order to maintain their services. Validity of such a subsidy and an amount of it should be assessed.
The passenger rapid boat line connecting the Osaki Kamijima Island and the mainland, which is the target of this study, has been in deficit and operated by being given the subsidy from the local government. In this study, validity of the subsidy to the line is assessed by analyses of its necessity and economical valuation on the basis of the data obtained from the questionnaire survey that was carried out to the islanders.
