Diverticulitis in the terminal ileum is uncommon. Past reports suggested that conservative therapy may be feasible to treat terminal ileum diverticulitis without perforation; however, there is no consensus on the therapeutic strategy for small bowel diverticulitis. We present a 37-year-old man who was referred to our hospital for sudden onset of abdominal pain and nausea. He was diagnosed with diverticulitis in the terminal ileum by computed tomography (CT). Tazobactam/piperacillin hydrate (18 g/day) was administered. The antibiotic treatment was maintained for 7 days, and the symptoms disappeared after the treatment. Thirty-eight days after antibiotic therapy, he noticed severe abdominal pain again. He was diagnosed with diverticulitis in terminal ileum which was flare-up of inflammation. He was given antibiotic therapy again. Nine days after antibiotic therapy, laparoscopy assisted right hemicolectomy and resection of 20 cm of terminal ileum were performed. Histopathology report confirmed multiple ileal diverticulitis. He was discharged from our hospital 12 days after the surgery. Colonoscopy was performed two months after the surgery and it revealed no finding suggesting inflammatory bowel disease. Surgical treatment should be taken into account as a potential treatment option to manage the diverticulitis in the terminal ileum even though it is not perforated.