The Shimanto River watershed has been one of the important cultural landscapes of Japan since February, 2009. One of the important landscape elements is inland fishery which has been conducted by local people for a long time. However, the number of successors is decreasing due to depopulation and a difficulty of economic independence. It might cause the traditional fishing styles to be vanished. In this study, the potential for ecotourism regarding inland fishery was measured to approach a practical solution of the problem. The important thing is to find out if there are enough fish to be conducted the ecotour in the watershed. Social scientific method was carried out. Questionnaire survey was conducted among fishermen in the watershed. As a result of a test of independence, the influence between two questions “Do you think that surplus fish for the ecotour exist?” and “Have you ever conducted an inland fishery tour?” are observed. It means that fishermen who have ever conducted a tour regarding inland fishery tend to answer that the river has enough fish to do the tour. The answers from the fishermen, who have ever done the tour, are more reliable on these questions. The proportion of the positive answers is beyond the negative answers’ among the fishermen who have ever done. This is the reason why we can say that the possibility of the ecotour is large in this watershed.