Japan consists of many islands. An island is surrounded by the sea and the transportation is generally inconvenient. Many islands are less favored with industrial development and they face a sharp decrease in population. In this study, Shimo-Gotoh island in Nagasaki Prefecture was selected in order to obtain the measures for slowing down the exodus of inhabitants. Nagasaki Prefecture has 588 islands of which 75 are inhabited. The improvement of the life of inhabitants in those islands have been one of the major issues for the prefectural government. Up to now relatively many researches have been made on the economy of those islands. Among them Gotohislands were selected for this study. Gotoh islands, however, consist of two districts; Kami (north) – and Shimo (south) - Gotoh. Fishery is a predominant industry in Kami-Gotoh. So it was considered that this district was not well suited for study, because the porpose of this study was to analyze theinter-relations between the industries located in an island. In Shimo-Gotohisland, in addition to traditional industries such as agricu1ture, fishery and some forestry, a silk - 1spinning factory, some workshops of apparel industry and fish –processing industry are located. The silk -spinning factory was established in 1980 and the output of the factory has been decreasing with decline of sericulture in the island. The output of apparel and fish-processing industries have been increasing. Thus Shimo-Gotoh island were selected for this study. And the spread effect and interrelations between industries were estimated with aid of inter -industry analysis. The study shows that two patterns are observed of the development of industries in the island. One is the development of exogenous industries. In this case, the industries located in the island have little relation to the resources of the island other than lavor force as apparel industry. The other is related to endogenous industries. The industries in this case have a close relation to the resources of the island as fishprocessingindustry, and the development of the industry of this kind may accelarateecomomic activities of related industries making use of the resources of island. In this study the concept of industry mix was introduced from a standpoint of fostering the inter-relations between industries. In order to overcome the disadvantages of the island, it is quite important to promote the development of endogenous industries and toforster the inter-relations between industries. They will help pave the way to generate new industries by islanders themselves.