The patient was a 45-year-old woman with diabetes mellitus and chronic kidney disease requiring dialysis. She was referred to our hospital with a chief complaint of an ulcer in the center of the left lower leg. The ulcer worsened despite critical limb ischemia revascularization. The femoral amputation wound was considered to have sufficient blood flow. However, the cut stump and inguinal wound opened, thereby requiring debridement and negative pressure wound therapy. The first ulcer in this case was not a toe ulcer, which is a characteristic of arteriosclerosis obliterans. However, the ulcer was located in the middle of the lower leg. Moreover, the ulcer occurred at the cut stump of the thigh and groin area that had no ischemic damage. As the painful ulcer progressed, we diagnosed the patient with calciphylaxis. We decided to discontinue oral warfarin and corrected serum calcium and phosphorus levels. Finally, these treatments healed the wounds.