A cutting device includes a fixing plate, a revolving cylinder, an annular cutting blade, and an ejection bar. The fixing plate defines a first through hole. The revolving cylinder is threadedly engaged in the first through hole and defines a second through hole. The cutting blade defines a third through hole and is attached to the revolving cylinder. The revolving cylinder is rotatable relative to the fixing plate to move the cutting blade between an extended position and a retracted position. In the extended position, the cutting blade cuts a surface of the workpiece to create a round blind crack in the surface thereof, a portion of the workpiece being surrounded by the blind crack. In the retracted position, the cutting blade is moved away from the workpiece. The ejection bar is configured for pushing the surrounded portion out of the workpiece.