A 41-year-old woman presented with sudden onset severe epigastric pain. She was diagnosed as having severe acute pancreatitis (SAP) with an APACHE II score of 10, and initially, general supportive therapy was performed. Because the patient's condition kept worsening, early laparoscopic surgery was performed. It revealed swelling, hemorrhagic necrosis of the pancreas, and massive fluid collection in the abdominal cavity. Kocherization and bursectomy were performed for these lesions, and drainage tubes were indwelled. The white blood cell count (WBC) and serum interleukin-6 value prominently improved shortly after the operation, and the WBC count remained at a low level. The patient gradually recovered and was finally discharged 39 days after her initial presentation. To summarize, we performed a successful exploration for SAP, and we found that postoperative continuous lavage effectively eliminated toxic enzymatic exudates in the abdominal cavity and prevent them from circulating. Regarding SAP with peritonitis, early laparoscopic surgery is very useful for determining the pathological extent of the disease and for selecting appropriate treatment options.