There were diverse theories and ideas within the thought of Japan in the 18th Century. This paper will examine the most important three currents - Gogaku, Kokugaku, and Rangaku - among others. The frame of thought in the Edo period is neo-Confucianism, although the topic is under debate whether neo-Confucianism was the dominant ideology of Edo bakufu. It is a fact that neo-Confucianism provided agendas and keywords of the intellectual world at the very least, so that the importance and influence of neo-Confucianism in the early Edo period cannot be ignored. In this sense, we can say the 17th century of Edo period is the era of neo-Confucianism. From the 18th century, however, this tendency of thought began to change. That is the escape, resistance, criticism, and transformation from neo-Confucianism. In the 18th century, Gogaku was developed within Confucianism. According to the appearance of Kokugaku and Rangaku, intellectual interest was heading toward the external world. This tendency toward change was influenced by Soraigaku. From Sorai to administrative thinkers of the 18th century, attention was paid to social and economic issues, and both scholars of Confucianism and Kokugaku who succeeded Gobunsigaku intensified their awareness and study of these issues. Through the development of Japanese thought in the 18th Century, we know that a number of diverse theories and thoughts were freely exchanged, and that the philosophical studies flourished.