In this article I discuss the impact of the Hyojangmyo (孝章廟) ritual, which was instituted by the royal family as a state rite (國家儀禮), on the religious culture of the Joseon dynasty by analyzing its development and characteristics. Crown Prince HyojangSeja (孝章世子) was the oldest son of King Yeongjo (英祖). In spite of the fact that he died early and childless, he became the object of ancestor worship. Originally, in a case such as this where a crown prince died without issue or was not of a higher generation than the king, he could not become the object of ancestor worship. Rites for the deceased crown prince at the Hyojangmyo were thus a clear contradiction of Confucian orthodoxy. Based on the principle of differentiating between proper (淫祀) and improper rituals (淫祀), it should have been classified as an improper ritual. However, it was officially adopted as part of the state rites without stirring any controversy. To fully understand the reason and motivations for this, this article presents two factors. The first motivating factor is that of the Sunhoemyo (順懷廟) and Sohyeonmyo (昭顯廟) rituals. Both were maintained after the death of the king who had created them. The second is the reorganization of state rites and strengthening of royal authority during the reigns of King Sukjong and King Yeongjo. A particular feature of the Hyojangmyo ritual is that it treats the object of worship as if his status as crown prince was still valid. Through the formative process of the Hyojangmyo ritual, we can see that primogeniture-focused patrilineage was not the only object of Confucian ancestor worship among the royal family: these also included the deceased from various descent lines. In addition, it shows us the meaning and the importance of the death of Crown Prince Hyojang in the formation of new institutions and in the expansion of the boundaries of existing institutions and principles. Through the formation of the Hyojangmyo ritual, an independent lineage of the childless Crown Prince was formed within the royal family.