Magnetic gears realize the system with maintenance-free, low noise and low vibration characteristics by non-contact power transformation. However, conventional magnetic gears are not suitable for the high speed drive because of the low mechanical strength due to permanent magnets of the high speed rotor. In addition, the gear efficiency is much decreased by increasing the eddy current loss in the magnets and core loss due to the harmonic fluxes. To overcome these problems, in this research, a novel Magnetic Multiple Spur Gear (MMSG) is proposed to achieve the high efficiency and to make downsizing the system. In this paper, the reason why the MMSG can realize the high torque density and high efficiency is clarified by focusing on the flux density distribution. In addition, the efficiency and loss of the prototype gear in the high speed region are verified by the experiment.