A bending operation system includes an elongated tubular portion including a bending portion, a first linear member and a second linear member which cause the bending portion to bend, and a drive portion which displaces the first linear member and the second linear member. The bending operation system further includes a first displacement detector which acquires a displacement of the first linear member as a first displacement, a second displacement detector which acquires a displacement of the second linear member as a second displacement, and a calculator which calculates operation assist information by use of one or both of the first displacement and the second displacement.
