A 60's man underwent a medical check-up and esophagogastroduodenoscopy revealed an exposed-type tumor at the ampulla of Vater. Endoscopic ultrasonography and intraductal ultrasonography showed a hypoechoic mass limited to the ampulla of Vater. Endoscopic retrograde cholangiopancreatography (ERCP) revealed a slightly dilated ventral pancreatic duct not connected to the dorsal duct. Endoscopic papillectomy was performed without pancreatic stent placement and his postprocedural course was uneventful. The specimen was histologically diagnosed as well-differentiated adenocarcinoma limited to the mucosa of the ampulla of Vater. Endoscopic papillectomy without pancreatic stent placement can be performed without a risk of post-ERCP pancreatitis for ampullary tumor limited to the mucosa of the ampulla of Vater associated with pancreas divisum.