A 57-year-old man was treated with lenvatinib for unresectable hepatocellular carcinoma(HCC). Thereafter, the tumor marker levels decreased, and the tumor became resectable. The patient underwent portal vein embolization followed by laparoscopic extended left lobectomy. The patient's postoperative course was uneventful, and the tumor marker levels remained within the normal range. No recurrence was observed 3 months after surgery. In recent years, the use of systemic chemotherapy with drugs, such as lenvatinib, followed by conversion surgery has been reported in some cases of unresectable HCC. The present case reports successful conversion surgery following lenvatinib treatment.