An electric bending operation device can be mounted to an insertion portion of a medical instrument for observation including an electric bending portion. The electric bending operation device includes: an insertion portion mounting mechanism a rotation mechanism an insertion portion operation section and a support column. The insertion portion mounting mechanism includes a pressing portion that is provided integrally with a rotary cylinder through which the insertion portion is passed and presses and holds the insertion portion. Switching can be performed between a state where the pressing portion presses the insertion portion and the rotary cylinder is integral with the insertion portion and a state where the insertion portion is advanced or retracted with respect to the rotary cylinder. The rotation mechanism is provided in the insertion portion mounting mechanism. The rotation mechanism rotates the rotary cylinder to rotate the insertion portion around an axis thereof when the rotary cylinder is integral with the insertion portion. The insertion portion operation section includes a bending portion operation section and a twisting operation portion. The bending portion operation section performs bending operation of the electric bending portion provided in the insertion portion. The twisting operation portion rotates the rotary cylinder to rotate the insertion portion. The support column integrally connects the insertion portion operation section and the insertion portion mounting mechanism.
