In 1980-82, the Second International Mathematics Study (SIMS) was conducted in 20 countries, including Japan. This study was conducted by the International Association for the Evaluation of Educational Achievement (IEA). This paper constitutes a summary of the research relating to the level of mathematics achievement of Japanese students. The tests administered to the students were designed to measure computation, comprehension, application, and analysis in the areas of: (1) sets, relations and functions; (2) number systems; (3) algebra; (4) geometry; (5) mathematical analysis; (6) probability and statistics; (7) measurement; and (8) finite mathematics. Scores on the tests were compared with the internationally averaged values of all 20 countries involved in the study. The achievement by Japanese students was found to be better than the international average in all content areas, but especially in the areas of geometry, algebra, and measurement. (TW)