On Awashima Island in Niigata prefecture, Japan, the tourist association conducts ecotourism specifically aimed at children. In this ecotourism, providing children with valid educational materials is important. Therefore, we have proposed an ecotourism support system that can provide video content as educational materials by using mobile phones and One-seg broadcasting. In an experimental evaluation of the proposed system, a content scheduler of the system has increased the number of accesses per hour to the ecotour page by offering appropriate content to tourists. As a result, a conversion rate of the ecotour page was 30.6% which is quite high, so One-seg broadcasting is useful for advertising ecotourism.