A compact X-ray source is required in various fields such as biological science and material development. At Waseda University, a table-top size soft X-ray source based on laser Compton scattering has been developed. Using 1047 nm laser beam (Nd:YLF) and 4.6 MeV electron beam generated from a photo-cathode RF-gun, we had already succeeded in generating laser Compton X-rays . The energies are within the "water window" region (250-500 eV)  which can be applied to biological studies. For good signal to noise (S/N) ratio and more photons, we remodeled our collision chamber and laser amplifier system. With these modifications, the X-ray photons detected by a micro channel plate (MCP) have increased tenfold to reach 312 /pulse. All the generated photons was estimated to be 3.28×104. Moreover, we succeeded in generating soft X-rays stably for more than 10 hours. Good S/N ratio stable X-rays have made it possible to observe the beam-laser interaction precisely.