Abstract
We study on a Mohr-Mascheroni theorem, which is the followings: If a construction problem is solved by euclidean tools(compass and ruler), then it can be solved using only compass. Though it is known that Mohr-Mascheroni theorem was proved by Mascheroni, but we have not any materials concerned with Mascheroni's work. In order to investigate Mohr-Mascheroni theorem, we analyze Euclid's Elements, and we draw some construction problems, which are essential for proving Mohr-Mascheroni theorem. We solve these problems using only compass. Though we don't solve all construction problems of Euclid's Elements, we can regard that Mohr-Mascheroni theorem is proved.