There is a rising interest for the phenomena caused by inelastic tunneling in the experiments using scanning tunneling microscope (STM).@footnote 1@ In this report, we show surface-diffusion of adsorbate is induced by inelastic tunneling of electron for the molecules of CO and ethylene on Pd(110) at 4.8K. When a certain amount of tunneling electron is dosed on a single adsorbate, the change of their bonding site along [1 0] direction is observed. We study this phenomenon systematically and found that the diffusion probability shows a very sharp increase at the bias voltage of 250 mV, which corresponds to the excitation of CO stretch vibrational mode. In similar manner, ethylene molecule adsorbed on the same surface is also enhanced to hop to the neighboring sites by irradiating electrons that correspond to the excitation of the internal stretching modes. These clearly demonstrate that the vibrational mode excited by inelastically tunneled electrons opens a route to induce hopping of the adsorbed molecules on surfaces. In the case of CO on Pd(110), thermal diffusion of CO was previously studied. At 100 K, one-dimensional CO arrays are formed and attaching and detaching of CO molecules are observed. The motion is restricted on [1 0] direction. The estimated diffusion barrier for a CO molecule in an array is ~180 meV, but the value for an isolated molecule should be much smaller in energy. Here we propose a model that the diffusion of CO is induced by an excitation of high lying vibrational mode (C-O stretch mode) which is further coupled with T-mode and R-mode through anharmonic coupling to induce surface diffusion . @FootnoteText@ @footnote 1@J.R. Hahn, H.J. Lee, and W. Ho, Phys. Rev. Lett. 85 1914 (2000) and references there in.