This paper presents design studies on a rotor for a high-speed homopolar type permanent magnet motor that can be applied to super chargers for automobiles, cordless stick vacuum cleaners and so forth. The stator comprises a core and a permanent magnet. The rotor is composed of only a core, resulting in enabling the removal of a retaining ring on the surface. Firstly, acceleration performance simulation using a prototype motor with a load blade was developed based on the data measured in an air compressor drive. Subsequently, the rotor shape design refinements based on three-dimensional (3D) finite element analysis were conducted to achieve the maximum torque and power required from a target application under a constraint of core stack length. The design refinement results proven by the acceleration performance of the developed simulation reveal that following the refinements to the rotor design, the homopolar type permanent magnet motor meets the requirement of the target application.