Intramural dissection of the esophagus is a rare esophageal disorder that is characterized by a long laceration between the esophageal mucosa and submucosa but without perforation. It reveals characteristic radiologic and endoscopic features. The etiology of intramural dissection of the esophagus remains uncertain. The most common presenting symptoms are sudden retrosternal pain, hematemesis, odynophagia, dysphagia, and back pain. Conservative management is usually thought to be adequate. We report a case of spontaneous intramural esophageal dissection, in which the symptom of dysphagia did not improve with the conservative management, and an endoscopic incision of the septum between true and false lumens using a needle-type diathermy knife was done safely and effectively.