We have been researching generating technology of underwater shock wave using high voltage discharge in water [1].Additionally,we aim to apply the underwater shock wave to a food processing [2].However,our device have disadvantage such as a slow generation cycle,excessive discharge energy.Therefore,purpose of this reserch is to develop the shock wave generating device such as lower charging energy and faster operating cycle.We developed the device based on Cockcroft-Walton circuit and Marx generator.The device have capacity of charging energy of 0.3kJ,operating cycle is 30 shot/minutes.In experiment,the voltage current characteristics was measured,and the underwater shock wave visualized(Figure 1)by schlieren method using a high speed camera for the purpose of to estimate the peak power and the shock wave.As a results,the peak power of 3.2MW was rapidly applied to the underwater electrode,the shock wave was observed such as that the propagation velocity of 1490m/s and the shock pressure of several MPa.It was shown that the device is benefit to the food processing.