An assistance tool that assists in moving a treatment device is provided. The assistance tool includes a flexible tube in which an insertion path is formed to insert the treatment device that is inserted into a channel in an insertion portion of an endoscope, a tube member that is coupled to the flexible tube and has a curved portion halfway of an overall length and in which an insertion path for the treatment device is formed, a coupling portion that is coupled to the tube member and is formed to couple the channel to the insertion path, and a holding portion that is attached to the flexible tube and holds the insertion portion or an operation portion that is coupled to the insertion portion.
