A method for laparoscopically preventing insufflation of the small bowel during gastric procedures includes applying an obstruction member at the pyloric sphincter to block the passage of gas from the gastric cavity into the small bowel and insufflating the gastric cavity. The heart valve apparatus includes a stent and a valve frame having a substantially cylindrical body defining a lumen. By irradiating the positioning mark with position detecting light from the side of the main surface of the dielectric layer and detecting reflected light, relative positioning between the wiring substrate workpiece and the exposure mask is based on the detection result. The interior container is removably received within the exterior container.