Most schwannomas occur in the head, neck, or limbs with a few cases occurring in the retroperitoneal space. In benign schwannoma occurring in the retroperitoneal space, tumors are most commonly located near the adrenal gland. Herein, we report on a 55-year-old Japanese man with benign schwannoma (6×4 cm) behind the lesser omental sac, which was removed under laparoscopy. Non-functioning neurogenic tumor was suspected as a differential diagnosis by computed tomography, ultrasonography, and magnetic resonance imaging, and the patient underwent laparoscopic resection of the tumor. Histologically, the resected tumor was diagnosed as benign schwannoma. The patient was discharged from our hospital on the tenth postoperative day without any complications. A laparoscopic surgical technique is safe and feasible for the diagnosis and treatment of retroperitoneal benign tumors such as schwannoma.