A dual-rotor motor in which inner slot angle φi is larger than outer slot angle φo. An inner notched portion is provided on both circumferential ends of an inner head. This inner notched portion provides a broader space between the inner head and an inner rotor toward both utmost ends of the inner head. An outer notched portion is provided on both circumferential ends of an outer head. This outer notched portion provides a broader space between the outer head and the outer rotor toward both utmost ends of the outer head.