An object of the invention is to provide an operation mechanism, an endoscope, and a manufacturing method that can reliably fix an operation wire to a member to be operated. According to an operation mechanism of an aspect of the invention, since a sleeve member is caulked in a caulked shape where a twisted shape of a plurality of strands of an operation wire is maintained, the sleeve member is caulked while the strands are maintained in an original line contact state. Accordingly, since damages to the strands caused by a point contact state of the strands do not occur, the tensile strength and bending durability of the operation wire are improved and the operation wire can be reliably fixed to a member to be operated. Further, since the sleeve member, which is externally fitted to the operation wire, is fixed to the member to be operated, other fixing members are not required. Accordingly, a fixing portion can be reduced in size.