A motor-driven machine tool unit having a stator unit and at least one rotor unit having a rotor shaft that is rotatable about an axis of rotation. The rotor unit includes at least one first bearing unit arranged in the end region of a tool and/or workpiece receptacle, and a second bearing unit arranged at the opposite end region for mounting the rotor shaft in the stator unit. At least one electrical power transmission unit for transmitting electrical power between the stator unit and the rotor unit is provided. The problem addressed by the invention is that of better satisfying the increasing demands on modern machine tools or machine tool units. This problem is solved by the electrical power transmission unit is arranged in the end region opposite the tool and/or workpiece holder and/or on the second bearing unit.