Nisinosima‐Sin To is a volcanic island newly born in autumn 1973 at Lat. 27° 14.5'N, Long. 140° 52.5'E, about 1,000 km south of Tokyo. The Maritime Safety Agency of Japan pursued the processes of submarine eruption, growth of the new volcanic island, and its topographic change by means of aerophotogrammetry, etc. Nisinosima‐Sin To began its volcanic activity in April 1973, and grew from a submarine volcano to a volcanic island; it became inactive in May 1974. The volcanic island formed during this period covered an area of about 240,000 m2at the maximum stage, which is now decreased to about 190,000 m2due to marine erosion. The height above sea level of the crater, or the highest point of the new island, became lower by 15 m, namely from 53 m in August 1974 to to 38 m in November 1978.