External mechanism for endoscope and endoscope system

An endoscope system comprising,

• an endoscope, and an external mechanism that can be attached to and detached from an operation portion of the endoscope,
• the endoscope comprising a bending knob provided in the operation portion and configured to bend a bending portion of an insertion portion when the bending knob is turned;
• the external mechanism comprising:
• a wheel configured to be engaged with the bending knob to turn the bending knob;
• a motor configured to generate driving force for rotating the wheel;
• a first operation switch configured to output a driving control signal for the motor;
• a container case that contains the wheel and the motor;
• a clamp with which the container case can be attached to and detached from the operation portion;
• a switch case turnably attached to the container case, when the clamp attaches the container case to the operation portion, the switch case being configured to turn between a first position that covers a part of the operation portion of the endoscope and a second position further away from the operation portion of the endoscope than the first position;
• and
• a dummy switch arranged on the switch case such that the dummy switch engages with a second operation switch arranged in the part of the operation portion when the switch case is in the first position, the dummy switch enabling the second operation switch to be operated by operation of the dummy switch when the switch case is in the first position,
• wherein the switch case includes a container portion for movably housing the first operation switch, the first operation switch being configured to output the driving control signal for the motor when the first operation switch is moved relative to the container portion.