Various magnetic micro-robots driven by an external magnetic field have recently been suggested for bio-medical application. The main benefit of control using an external magnetic field that it is wireless and the robot is battery-free. Most locomotion methods of magnetic micro-robots depend on swimming method using an alternatiing magnetic field. In addition, a rotating magnetic field has been used for the spiral swimming method. In this paper, we propose a new locomotion method and mechanism within the rotating magnetic field using a three-axis Helmholtz coil. The proposed mechanism is based on snake-like skeletal motion that consists of an NdFeB spherical magnet, artificial spine, and ribs. This structure creates an undulatory motion based on dynamic rotation of both roll and yaw motions by magnetic torque. The proposed mechanism and driving method shows excellent mobility in various environments.