Disclosed herein is a stent (10) implanted in the body of a patient. The stent includes a hollow cylindrical stent body (15) which is made of a super-elastic shape memory alloy and has an expanded diameter part (13) on one end thereof, and a support stent (30) which has an elastic spherical structure and is fitted over the cylindrical stent body behind the expanded diameter part. The stent is implanted in the body such that food that has passed through the stomach is prevented from mixing with bile or pancreatic juice in the duodenum and moves directly into the small intestine to prevent the duodenum from absorbing nutrients of the food while the small intestine directly digests the food and absorbs the nutrients, thus minimizing a nutrient absorption rate, thereby preventing the obesity of the patient.
