Provided are an endoscope and a hardness adjustment device configured so that an arrangement space of built-in components in an operation portion can be ensured and that burden on a coil spring and a wire can be reduced. In an operation portion, a retained portion of a coil spring unit is retained at a first radial position by a coil spring holder as a first retainer, and a base end portion of a wire unit is retained at a second radial position by a wire holder as a second retainer. A base end portion of the coil spring unit is retained at a third radial position by a coil spring contact portion as a third retainer.
