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 12, a retained portion 51 of a coil spring unit CU is retained at a first radial position P1 by a coil spring holder 60 as a first retainer, and a base end portion 49 of a wire unit WU is retained at a second radial position P2 by a wire holder 52 as a second retainer. A base end portion 47 of the coil spring unit CU is retained at a third radial position P3 by a coil spring contact portion 58 as a third retainer.
