An introduction device includes an operation main body, a bending section capable of bending in a first direction and a second direction, a first rotary body configured to be operated at a time of bending the bending section in the first direction, and a second rotary body configured to be operated at a time of bending the bending section in the second direction, the second rotary body being configured such that a part of an outer edge is located on an extension plane which is defined by extending the first surface, or the part of the outer edge is located more on the distal-end direction side of the first shaft portion than the extension plane.