This research proposes a navigating and drilling spiral microrobot actuated by a magnetic gradient and rotating uniform magnetic field to unclog blocked human blood vessels. The proposed spiral microrobot consists of a cylindrical body that contains a cylindrical magnet and spiral drilling blades on the shaft. The cylindrical magnet can rotate freely inside the magnet slot of the body and align in any direction by applying an external uniform magnetic field. The spiral microrobot is prototyped by 3-D printing technology with ultraviolet curable acrylic plastic, then demonstrated by various experiments. These experiments show that the proposed microrobot successfully performs navigating and drilling motions, thus validating the effectiveness of the proposed spiral microrobot.