A living-wall fixing tool for use with endoscopes, including first and second fixing members, first and second cord like members, an elastic stopper, and a slackening means. The first fixing member is to be inserted into a second organ through a hole formed through first and second organs. The second fixing member is to be detained in the first organ. The stopper is slidably mounted on the first cord-like member. The slackening means slackens the first cord-like member. When the slackening means is operated, the second cord-like member is pulled, whereby the first fixing member is pulled into the first organ through the hole.