[en] In research Center for Nuclear Physics, Osaka University, the cyclotron cascade project of connecting the ring cyclotron of energy constant K = 400 as the booster to the existing AVF cyclotron was completed in the spring of 1991, and the adjustment of beam acceleration and test experiment were started in autumn. The vacuum system of this cyclotron was already reported in detail, acoordingly in this report, the present status is described. In the factory, the vacuum tank of 10 m diameter was not able to be assembled, therefore, vacuum test was carried out on the divided parts, and after connecting them at the site, the general test was performed. By the exhaust of nearly 10 h from the atmospheric pressure, the pressure of 2 x 10^-5 Pa was attained. As for protons, the adjustment of acceleration up to 400 MeV was carried out. The construction and the function of the ring cyclotron are explained. As for the exhaust system, the shortening of the time for exhausting so that beam acceleration can be done was endeavored. The operation and monitoring of the cyclotron are explained. (K.I.)