A rotor (10) for a rotary electric machine (1) comprises a rotation shaft (11), and a plurality of rotor cores (120-129) fixed to the rotation shaft (11) and axially split. The rotor cores (120-129) have outer peripheral surfaces (120A-129A) with a circular cross section. Permanent magnets (13) extending through the rotor cores (120-129) are arranged at equal circumferential intervals. Voids (120B-129B) extending axially through the rotor cores (120-129) are formed between the outer peripheral surfaces (120A-129A) and the permanent magnets (13). The voids (120B-129B) of two adjacent rotor cores (120-129) are formed at circumferentially different positions, thereby being capable of suppressing the cogging torque without introducing a reduction in output torque.