A medical system including: a plurality of medical instruments each including an elongated insertion section that can be inserted into the body from the body surface； fixing parts that are provided in the insertion sections of the plurality of medical instruments, respectively, at positions away from the distal ends toward the proximal end side and that can be coupled with or separated from each other； and manipulation parts that are provided at the proximal end side of the insertion sections and that are used to manipulate coupling and separation of the fixing parts.
