Procedural methods are provided that are capable of forming a protuberant region, in which the surface of a living body protrudes, in a less-invasive manner and a medical device capable of forming the protuberant region in a less-invasive manner. A procedural method for forming a protuberant region, in which a surface of a living body protrudes, includes an introduction step of introducing a container having flexibility into the living body, a protuberant region forming step of forming the protuberant region, in which the surface of the living body protrudes, by filling the container with a filling material to expand the container, and a placement step of placing the expanded container in the living body.
