Yamamoto, Y. JACoW Publishing Geneva, Switzerland In STF at KEK, as the operational demonstration of the SRF accelerator for ILC, the STF-2 cryomodules (CM¹⁺CM2a: one and half size CM with 12 cavities) have achieved 33 MV/m as average accelerating gradient estimated from the beam energy with 7 cavities in Mar/2019. After that, one cavity with the lowest performance installed in CM2a was replaced with one nitrogen-infused cavity developed for High-Q/High-G R&D between Japan and US. From Apr/2021, the beam operation started again and those CMs achieved 33 MV/m as average accelerating gradient with 9 cavities including one nitrogen-infused cavity. This is the very important milestone for ILC. In this report, the detailed results will be presented.