In Joseon, the term of ‘religion(宗敎)’ was not used. The term of religion was coined during the Japanese colonial era, and Confucianism was excluded from religion to pseudo religion and included into the area of superstition or study. This piece of writing begins with the question of how we could have introduced Confucianism if it had not been for the colonial era. This thesis aims at revealing religiosity in Toegye’s thoughts through the subject of ‘Toegye’s Sangje(上帝) and Li(理)’ and examining spontaneous religiosity. Since the ancient times including Joseon, ancestral rites for the highest ancestor god, Sangje, had been held, which can be also verified through the writings of Mokeun and Sambong. Mentions about Sangje are also easily found in Toegye’s writings. In Seonghaksipdo, the world view of ｢Taegeukdo｣is found to pursue a cosmic family community. A family is a sacred place to experience Taegeuk, and Ohryun is a holy order to maintain the community. As the conclusion of the discussion over Sadan and Chiljeong with Gobong for 8 years, Toegye distinguished Jungdo(中圖) from Hado(下圖) in ｢ Simtongseongjeongdo｣of Seonghaksipdo, and said Sadan(四端) of Hado was ‘Libal(理發)’, and Chiljeong(七情) was ‘Gibal(氣發)’. Regarding Hado, in the sense of the condition that an object is connected to oneself, the sacred sense of Sadan was separated.