Yamamoto, Y. JACoW Publishing Geneva, Switzerland The STF-2 accelerator with fourteen 9-cell superconducting cavities at KEK has achieved many milestones for the International Linear Collider (ILC) project since 2019. The main achievements are the beam acceleration at 33 MV/m with nine cavities, the max. beam energy of 384 MeV, the beam power of 6 kW, the beam operation with 5.8 mA per bunch (21.5 ¿A as the beam intensity), the beam emittance of 5 mm mrad, the Low-Level RF control to compensate with heavy beam loading, etc. On the other hand, in these cool-down tests, the performance of cavities has changed including the radiation level. In this talk, these achievements and experiences in the STF-2 accelerator will be presented.