Objective of the study was to investigate characteristics and meanings of the agricultural extension work during the period of Japanese $rule(1906{sim}1945)$ through historical review on the work. The agricultural extension work during the period of Japanese rule was categorized into six patterns such as agricultural extension work by (1) government agricultural administration system, (2) agricultural experiment/research institute, (3) public school, (4) through the movement of rural development(Nong-chon-Jinheung Undong), (5) pro-government private organization, and (6) pure private organization. In conclusion, the characteristics of the extension work were defined; 1) a tool and/or method for colonial rule, 2) non-democratic and top-down extension work by administration, 3) authoritative and coercive work initiated by governmental system, 4) nation wide work of cooperation with public and private organization, 5) extension work focused on production increasing food and industrial materials, and 6) extension work initiated by government system without participation of pure private organization. The meanings of the extension work were reviewed in two ways. Firstly, in macro point of view, the work has negative meaning that was utilized as a tool and/or method for Japanese colonial rule, since the extension work was implemented under the direction of agricultural policy and was also directly related to the policy of Japanese colonial government. Secondly, in micro point of view, the work has significant meaning either negative or positive such as 1) beginning of modernized extension work based on experiment and research, 2) introduction of forcible agricultural extension work, 3) inducement of distrust tendency to agricultural policy and agricultural extension work, 4) establishment of basis in hardware of agricultural extension work, 5) production of experience in software of agricultural extension work, and 6) improvement of recognition toward scientific farming and improvement of level in agricultural techniques.