This paper attempts to grasp the meaning of the Article 27 (1) of the Constitution of the Republic of Korea which provides that "All citizens shall have the right to trial in conformity with the Act by judges qualified under the Constitution and the Act." Many scholars have scrutinized the meaning of the provision, but the meaning of the concept of "right to trial" itself has never been fully shed in the light of legal interpretation and argumentation. It goes through different path from what has been suggested either by theories of legal argumentation or legal reasoning, or by theories concerning the meaning of rule of law in that it pursues what J. Waldron calls right－based arguments rather than duty－based or aim－based arguments. It concludes that the right to trial is not just a right to the conclusive directives by which our behavior shall be guided, but also a right for the reason be given. To put it in a different word, the right to trial is a right to nonarbitrary judgment in public decision making, especially in the court`s decisions.