A composite mode transducer for dissipating heat generated by a heat generating element is disclosed. The composite mode transducer includes a transducing module and connection elements. The transducing module includes first and second transducing elements connected in parallel. The connection elements are connected to resonance nodes of the first and second transducing elements. The first and second transducing elements are driven by a multiple-frequency resonance circuit, to produce resonance vibration of composite modes at resonance vibration frequencies of the system. The resulting advantages by using the composite mode transducer are: elimination of local stress concentration, and enhancement of efficiency, endurance and stability of the system. Accordingly, drawbacks of the prior art are overcome. The present invention further provides a cooling device with the composite mode transducer.