The aim of this paper is to examine the organization of aguricultural extension in the College of Agticulture at Cornell University in 1894-1917. Having become clear through this paper is that some genealogys existed about the organization. They will roughly be classified into four until they result in birth of "The Extension Servise" in 1917, which is the central office of cooperative extension work in New York State. They are the genealogy which starts on "The Farmer's Reading Course" and stands in a row in an extention office and an department of extension teaching, the genealogy which resulted in foundation of a departments from "Nature Study" or "Farmer's Wives Readhing Course", the genealogy of the departments of subject-matter which took charge of experimental work, and the genealogy of a farm bureau office. The system formed by some such systems gathered for organization of the agricultural extension, and the principle of building the latest system was acting on it. Then, Why has the Extension Service unified the extension work of different charactor? First, the idea which Bailey held up is recognized in common between each enterprise. To be sure, the "rural citizen" whom Bailey says was a character of a man which is based on the United States-sense of values which had risen those days, and is easy to share among the staff of an extended enterprise. Second, it is considered for it to be important to have had fund right of management.