In this paper, I examined the characteristics of social work in the 1920s through two police officers` ideas on social work under the ``cultural rule``. Social work is, in a broad sense, the institutions and practices established in the progress of industrial society, for preventing poverty and for securing social stability. Since March First Independence Movement, social work in Korea took a role as aggressive security measures and policies to protect civilians. Under the ``cultural rule``, based on the division policy on duality of pro-Japanese and anti-Japanese or rioters/civilians, the administration of social work was closely related with the police administration. Among those administrators, it was Matsui Shigeru(松井茂) and Maruyama Tsurukichi(丸山?吉), both of whom were police officers, that tried to find out the relationship of the police and ordinary people the most hardest way. Those two representatively showed up as a new type of police officers/administrators who prevented people`s resistance against colonial rule in advance and administrate everyday lives of Koreans by increasing direct contacts with needy population. Maruyama and Matsui also thought about the basic frame work surrounding the police and people through their own experience in colonized Chosun, coming up with social work for preventing poverty and crimes with the names of ``people`s police`` and ``prevention police``. However, police officers engaged with crackdown on the ``mobs`` in the border areas did not accept their idea, saying it was only idealism which did not fit in reality. Maruyama and Matsui`s plans fell into danger of self-contradiction, facing colonial reality. Matsui suggested that there should be a strategy on the ``cultural police officers`` and ``militaristic training``, which revealed the dilemma between reality and ideal. In result, the ``colonial rule`` and ``social work`` are destined to contradict each other and only worked by dividing ``rioters`` and ``civilians``. We can conclude that social work proposed by police officers in the 1920s was the reverse side of the coin of oppressing the ``rioters`` fighting for independence.