An endoscope including an insertion portion which is provided with a channel to insert a treatment instrument therethrough, an operation portion which is operated the insertion portion, and an operation lever which holds and moves the treatment instrument to transmit force of the operation to the treatment instrument and an assistant instrument which assists the movement of the treatment instrument, the assistant instrument comprising a flexible tube in which the insertion path is formed to insert the treatment instrument, a coupling portion which is formed so that the channel is coupled to the insertion path, and a holding portion which is attached to the vicinity of the other end of the flexible tube and which holds the operation portion so that the other end of the flexible tube faces toward the side where the operation lever is disposed.
