Saltpeter is an important material for making gunpowder. Saltpeter was not produced naturally in Japan. Known artificial methods for making Saltpeter include the “Kodo-hou”, using underfloor soils, and the “Baiyou-hou”, using soil mixed with silkworm feces and wild grasses. These are valuable historical science technologies that have been passed down for about 300 years until the beginning of the Meiji era. The science of Saltpeter is considered to be a comprehensive science that transcends subject areas such as History, Chemistry, Biochemistry, Global Environment, and Geopolitics. The production methods described in historical records in the Edo era require a large amount of materials including soils and wood ashes as well as a long time. In order to put this into practice in educational settings, a simple and small-scale Saltpeter Making Method is required. We have therefore developed a simple method of small-scale Saltpeter Making of the “Kodo-hou”, which was the most popular throughout the country during the Edo era. The science of Saltpeter Making can be expected to spread to the field of global environment in secondary and higher education, and is suitable as a Comprehensive Science teaching material that goes beyond the subject area.