A coreless motor comprises a motor housing having a bearing, a rotor mounted within the housing, rotatably supported within the bearing and having a plurality of coils constituting a pancake coil, a permanent magnet stator mounted within the housing and disposed opposite to the rotor, in which the stator is arranged opposite to an effective coil section of the pancake coil and thus the rotor, and an annular spacing is formed opposite to an outer peripheral portion other than the effective coil section of the rotor so that a balance adjusting member for the rotor as well as an electrical part associated with the coreless motor can be provided in the annular spacing within the motor housing.