Paul Natorp is better known as a key figure of Neo-Kantian epistemology than as a great educationist. This paper discusses the affinity for Natorp's theory of education in Japan in the first decades of the twentieth century. It presents an overview of Natorp's educational way of thinking and analyses the interest of Japanese educationists in the educational thought encapsulated in the conception of Natorp's educational theory, which he called "Sozialpädagogik." Addressing the debate around Natorp's "Sozialpädagogik" within the Japanese national community of scholars, key points of the inception of the theory in Japan are examined, central scholars involved are identified, and the impact of Natorp's conception on the Japanese philosophy of education and educational practice is considered.