Duodenal diverticula are frequently observed in upper gastrointestinal endoscopies or upper gastrointestinal series. Most duodenal diverticula are asymptomatic, and complications are rare, however, diverticula occasionally result in diverticulitis, hemorrhage, obstruction, perforation, or sepsis. Most ingested foreign bodies are passed spontaneously and evacuated through gastrointestinal movement, but, if these foreign bodies are sharp and become impacted in a pathological lesion, such as a diverticulum, the risk of complications can be very high. In this paper, we report on a case of duodenal diverticulitis resulting from impacted bone-like food material. In this case, the food-material-induced diverticulitis showed spontaneous improvement through supportive care.