PROBLEM TO BE SOLVED: To provide an operation section for an in-aperture introduction device capable of widening the movable range of the thumb with the operational feeling of a bending operation knob remaining unchanged as much as possible when the bending operation knob is operated while it is gripped by a user.SOLUTION: The operation section for an in-aperture introduction device includes a universal cord connector 44 for extending a universal cord. The connector 44 has a first to third support areas 92, 94, 96, to which a users hand is applied, continued from a side closer to a pressing force valve unit arranging surface toward a side closer to a user opposing surface. The connector is located in a position where the second support area 94 which is closer to an insertion section relative to the first and third support areas 92, 96 is within an area between the user opposing surface and the pressing force valve unit arranging surface and the second support area is closer to the insertion section than the center axis of the bending operation knob is.
