A treatment instrument includes a treatment section treating a target of treatment such as a living tissue. The treatment section has an outer surface. A first resin film (first resin coating) covers part of the outer surface of the treatment section. A second resin film (second resin coating), which is formed of a material different from the first resin coating, covers at least a boundary between a region covered by the first resin film and a region not covered by the first resin film on the outer surface of the treatment section.
