Abstract: A plurality of sheets made of an elastic material such as vinyl and polypropylene are joined together by high-frequency gluing to form an airtight bag body. Then, the bag body is inflated by being filled with air to form a mannequin resembling the shapes of the upper and lower halves of a body. Regarding an upper bag body portion resembling the upper half of the body and a lower bag body portion resembling the lower half thereof, gussets are coupled through curved junction lines with sheets that form the respective base parts. A joining jig is used to join the sheets, thereby forming an airtight bag body. The foregoing provides an inflatable mannequin and a method of manufacturing the same that can express a natural and realistic body shape and that never damage the brand image of clothes a person who sees the mannequin wearing the clothes has.