The Beam Physics Laboratory of Hiroshima University studys photo-cathode for future acceleators by using a photo-cathode test bench. It aims to develop a cathode with the higher quantum efficiency and longer-lifetime. GaAs with Negative Electron Affinity (NEA) surface is one of the best cathode among the advanced cathode matrials. The NEA surface is essential to activate it as an electron source. It is well known that the NEA GaAs photo-cathode needs extremely high vacuum, because it is easily damaged. To study the detail process of the cathode property degradation by the damage, we construct a photo-cathode test bench with an extremely high vacuum quality based on a cryo-pump (2700l/s) and a NEG pump (1900l/s). The vacuum chamber is made of titanium (TP340) for low outgassing rate. We alredy obtain 1.7E-9Pa only with the cryo-pump. In this article, the test bench is briefly explained and the results of the first vacuum test is presented.