The corrosion resin-casts and the tissue preparations of the digestive diverticula (Azan staining) of the Japanese razor-clam, Solen strictus were observed. The resin-casts were made of the prepolymerization methyl methacrylate (MercoxCL-2R) containing 10 % Mercox MA. The digestive diverticula developed between the intestine and the oesophagus in he ventral side of stomach. After extending from the stomach, the intestine with complicated spiral structure descended lengthways in the central space of the foot and ascended lengthways in the abdomen. The style-sac separating from the intestine extended from the stomach into the central space of the foot. The origins of the ducts opened at 2 embayments on the stomach near the esophageal region. Each tubule separately extended at the end of the duct.