In recent years, HITV therapy, which cures cancer by improving the immunity of patients, has attracted attention. In this therapy, high puncture skills are required for physicians because dendritic cells are injected directly into the tumor using a fine needle. In order to solve this problem, we developed a CT-guided needle insertion robot “IRIS” that provides accurate puncture of a fine needle. In this study, we evaluated the puncture accuracy using an abdominal Biopsy phantom as a feasibility study of the total system. As a result, the puncture accuracy was less than the required accuracy ± 3 mm, suggesting the usefulness of IRIS for practical use.