The present, there are no evident standards about facilities of minimum-sized kindergarten and lower grades elementary school. So, there are many serious obstacles that related laws and regulations, planning for facilities and scales in this country. Accordingly, this study proposed the concept, type, and size of minimum-sized kindergarten and lower grades elementary school, in case big cities of high density. 1. The concept of minimum-sized kindergarten and lower grades elementary school is defined to the large scale school and class, that integration of children of kindergarten into lower grades elementary school. 2. The type of minimum-sized kindergarten and lower grades elementary school is classified into branch school type and detached school type. The former is located in the main elementary school, The latter is separated from the main elementary school. And each type is classified into singleness case and attached case. 3. The number of students per minimum-sized kindergarten and lower grades elementary school is hold from two hundred children to three hundred children in 12 classes, but suitability is from one hundred to two hundred children. And class sizes proposed $20{sim}25$ children in minimum-sized kindergarten and $25{sim}30$ children in lower grades elementary school.