A rotor device capable of dissipating heat and resisting foreign objects includes a hub and a shield case. The hub has a closed wall and a hub wall connecting with the closed wall and the closed wall at least has a hub hole. The shield case is mounted in the hub and has an upper wall neighboring the closed wall and a circumferential wall connecting with the upper wall. The upper wall at least has a through hole offsetting the hub hole to allow the fluid passing through the hub hole and the through hole for performing heat dissipation and preventing the foreign objects from falling into the shield case via the hub hole and the through hole.