Energy harvesting from noise is a paradigm proposed by the theory of stochastic resonances. We demonstrate that the random switching of a hydrogen (H-2) molecule can drive the oscillation of a macroscopic mechanical resonator. The H-2 motion was activated by tunneling electrons and caused fluctuations of the forces sensed by the tip of a noncontact atomic force microscope. The stochastic molecular noise and the periodic oscillation of the tip were coupled in a concerted dynamic that drives the system into self-oscillation. This phenomenon could be a way for enhancing the transfer of energy from incoherent sources into coherent dynamics of a molecular engine.