A heat dissipation module includes a housing, and a fan including an outer frame, a first rotor, a base, a second rotor and a driving device. The first rotor includes a shaft, a first hub and a plurality of first rotor blades disposed around the first hub. The base is disposed in the outer frame. The second rotor includes a plurality of second rotor blades, and is coupled to the shaft of the first rotor and disposed next to the first rotor. The driving device is supported by the base for driving the first rotor and the second rotor simultaneously.