An 80-year-old man underwent laparoscopic distal gastrectomy, D2 lymphadenectomy, and Billroth Ⅰ reconstruction for gastric cancer. The short gastric artery and vein were completely preserved. The patient developed a fever on the second postoperative day, and a blood test on the third day showed high inflammation findings, and contrast-enhanced CT scan revealed decreased gastric wall blood flow of the anal side of the remnant stomach. When contrast-enhanced CT was performed again 7 days after the surgery to re-evaluate the condition, there was no improvement in the decreased blood flow in the remnant stomach, so the diagnosis of remnant gastric necrosis was made. Total remnant gastrectomy, Roux-en-Y reconstruction were performed. Histopathologically, the remnant stomach was found to have full-thickness necrosis on the anal side. The stomach has a well-developed intramural blood flow network, so blood flow disorders in the remnant stomach is rare. However, there are individual differences in the blood flow network within the gastric wall, and if decreased blood flow is suspected, ICG fluorescence imaging should be performed and consideration should be given to changing the surgical method to additional gastrectomy or total gastrectomy.