In this study, $20;Nm^3/hr$ scale compact hydrogen generator which can be apply to the hydrogen station was manufactured and tested. The design of $20;Nm^3/hr$ scale compact hydrogen generator was upgraded on the base of $5;Nm^3/hr$ scale plate hydrogen generator concept stacking the plate reactors. Ideas for improving system efficiency such as heat recovery from the exhaust, exhaust duct which is especially design for plate type reactor, reinforcement of insulation, enlargement of heat exchange area of reactor, introduction of desulphurizer reactor and PROX rector in a compact design etc. were applied. From the performance test, we can learn that the $20;Nm^3/hr$ scale compact hydrogen generator can be operated steadily at 100% road condition and the methane conversion of over 94%(at S/C=3.75) was obtained. This result shows that the concept of plate type hydrogen generator can be scale-up to the $20;Nm^3/hr$ scale and fit for hydrogen generator for on site hydrogen station application.