The patient was a male in his 70s with a history of distal gastrectomy and Billroth-I reconstruction. He was suspected of having esophageal achalasia and was started on calcium blockers in X - 2 year. The symptoms worsened, and he presented to our hospital in X year. We diagnosed esophageal achalasia (Chicago classification ver. 3.0; type I), and conducted per-oral endoscopic myotomy (POEM). His postoperative course was uneventful with no postoperative symptoms. In cases of esophageal achalasia following distal gastrectomy, it is important to consider adhesions, mobility of the remaining stomach, and preservation of the short gastric artery and vein. Since the Heller-Dor operation can be difficult, POEM may be a reasonable alternative in these cases.