A bending operation system (100) includes an elongated tubular portion (110) including a bending portion (115), a first linear member (122) and a second linear member (124) which cause the bending portion to bend, and a drive portion (132) which displaces the first linear member and the second linear member. The bending operation system further includes a first displacement detector (136) which acquires a displacement of the first linear member as a first displacement, a second displacement detector (138) which acquires a displacement of the second linear member as a second displacement, and a calculator (140) which calculates operation assist information by use of one or both of the first displacement and the second displacement.
