Design of a micropump is important topic for controlling solution flow in a microchip 1). In this study, we newly fabricated a new electrochemically controllable micropumping system which operates by creating a concentration gradient of protons on two gold microelectrodes. Figure 1 show a schematic illustration of the principle of the pumping system. When anodic and cathodic reactions of hydrogen peroxide occurs on the each gold electrode surface, protons generated on the anode flow thorough the cathode. The protons are normally hydrated in an aqueous solution. Thus, localized water flow generates near the gold microelectrode surfaces. The gold microelectrodes (5 נ100 um2) were fabricated by photolithography. A microchannel in a microchip was formed by using polydimethylsiloxane (PDMS, 500 um width, 50 um height, 2.5 cm length). 5% hydrogen peroxide solution containing fluorescent substance- modified polystyrene (PS) particle was filled in the microchannel. A polarization curve was measured by using a potentiostat. Current increase was observed from 0 V. Current noise due to oxygenbubble generation occurred when applying the voltage of 0.6 V. Thus the moving direction of the polystyrene particles were observed using a fluorescent microscope while applying a constant voltage of 0.5 V between the gold microelectrodes. PS particles were adsorbed electrostatically on the anode surface when applied a constant voltage of 0.5 V. Next, when stopping the voltage application, the PS particles drastically moved opposite direction of the proton flow (Fig. 1). It is considered that the PS particles moved due to the reaction of water flow 2). We discussed in the moving principle more detail in our presentation. Reference 1) H. Zhang, W. Duan, M. Lu, X. Zhao, T. J. Huang and A. Sen, Acs Nano, 8 (2014) 8537-8542. 2) J. Wang, Acs Nano, 3 (2009) 4-9. Figure 1