本論文旨在探討日本德川時期，大阪懷德堂中井履軒《中庸》經解的旨趣與內涵，並藉由履軒《中庸逢原》的分析與梳理，考察履軒如何在理解與攻駁朱子《中庸章句》的同時並重建自己的系統。藉由本文的研究，履軒的經解進路有下列五項：（1）以實證的角度審視思想上的玄思義理。（2）將玄思義理的超越特質置回於歷史脈絡中去重新審視。（3）以文獻辨偽的治學方法去審視文獻來源是否真實或虛偽。（4）以漢唐經師文字訓詁之學去審視玄思義理的創造性詮釋。（5）以人為本位及其所圍繞的人事與現世精神，去審視玄思義理物我無別的一理萬殊。同時，本文亦嘗試梳理履軒的《中庸逢原》及其相關著作，構築其道學的系統，並分別於道統論、天道論、心性論、工夫論、體用論五項議題中探討其內容，展示履軒具有攻駁朱子的經解系統及宋明理學共法的特點。

This article seeks to investigate the research on Zhongyong (Doctrine of the mean) undertaken by Nakai Riken, a scholar from the Kaitokudō Institute in Ōsaka, Japan in the Tokugawa period. By reference to Nakai’s analyses in his work Zhongyong fengyuan, this article examines how he understood and refuted Zhu Xi’s work Zhongyong zhangju while reconstructing his own system. This article identifies five features in Nakai’s works: (1) inspecting metaphysical argumentation with positivism; (2) reviewing the transcendental quality of metaphysical argumentation by bringing it back in the context of history; (3) using the method of literature verification to examine whether the sources are authentic and credible; (4) scrutinizing the creative interpretations of metaphysical thoughts in light of Han and Tang scholars’ exegeses; and (5) probing the ideas of “everything evolving from one principle” and “the harmonization of objects and ego” in a human-based and secular spirit. Besides, this article attempts to collate Nakai’s Zhongyong fengyuan and related writings, so as to construct his system of neo-Confucianism. Moreover, this article discusses the contents of Nakai’s works in terms of Confucian orthodoxy, natural law, human nature, self-cultivation, and essence-function, thereby revealing Nakai’s attributes of refuting Zhu’s annotation system as well as the shared principles between his works and neo-Confucianism.