Provided is a machine for inspecting ferrules of an optical connector and a method thereof. A fixture arranges the ferrules on a rectangular system to inspect the ferrules. A robot centers first ferrule on a optical system and focuses the first ferrule on the optical system. The optical system includes two cameras for photographing inside diameter image data and outside diameter image data of the ferrule. While the robot moves sequentially the optical system and remaining ferrules, all the inside and outside diameter image data of the ferrules are in sequence obtained by the optical system. Each inside and outside diameter and eccentricity of the ferrules are calculated by the obtained inside and outside diameter image data via a computer program.