Under a scanning electron microscope, the microcirculation of normal and pathological stomachs was observed by a corrosion casting technique. This improved approach has been in the microvascular pattern of gastric ulcers to clarify its non-healing and recurring tendency. In the case of a normal rat, arteries, upon penetrating the serosa and immediately branched into capillaries at the base of the gastric gland. These mucosal capillaries run upward in more or less straight lines from the submucosal plexus toward the surface and continued to the vascular net on the mucosal surface. Part of the vascular net continued into a descending collecting venule which ran downward in a straight line, increasing in diameter and continuing into a collecting vein. An arteriovenous anastomotic channel was found between the artery and vein of the submucosal plexus. Although the microvascular pattern of the normal human stomach was little more complicated than that of the rat, its basic pattern was the much same. In the case of an experimental chronic gastric ulcer (acetic acid ulcer by Okabe), there are two unusual vascular structures, i.e., increased vessels and radiating vessels; histologically they represent zone of granulation and scar, these vessels are not observed horizontal anastomoses of each other. In particular, there are horizontal anastomose in the least between this vessel in scar and the vessel of the adjacent area. By the effects of the vagotomy and the drug (Gefarnate), this horizontal anastomose not change for the better during observation. In the case of a human chronic gastric ulcer, this particular pattern on the microcirculation was the much same. As a result of these observation, this particular pattern on the microcirculation can readily assumed that healing of deep ulcer is difficult. If it should heal, there appear weak points of blood supply, for the regenerated epithelium is supplied only by the poor scar vessels.