A coreless three-phase DC motor comprising a coil type armature formed with insulated windings. The armature is of a disc- or cylindrical-shape and is set rotatably against a field magnet provided with 2n magnetic poles N and S magnetized in equal angular widths. On the surface of the armature there are 3n/2 three-phase armature coils, wherein the angular width of each of the coils is equal to the width of the field magnet pole, the coils of each phase are shifted by 180.degree. of electrical angle from each other, and all the armature coils are arranged at equal angular intervals and not superimposedly with respect to one another.