A manipulator operation system comprising: a treatment instrument distal end movement control section having: an endoscope treatment instrument having a bending portion bendable in a desired direction and a distal end portion that is directly or indirectly coupled with the bending portion and has a treatment instrument configured to give a diseased part a treatment; a bending driving section configured to drive the bending portion to bend; and a bending operating section configured to operate the bending driving section to bend the bending portion, wherein the manipulator operation system further comprises an imaging mechanism having an imaging section that includes an optical system having a desired field curvature, configured to image the distal end portion and the bending portion by using the optical system, and provided separately from the endoscope treatment instrument, wherein the desired field curvature of the optical system results in an image distortion of a taken image that is taken by the imaging section and has the desired field curvature; an observing mechanism having a display section configured to display as an observation image the taken image that is taken by the imaging section and has the desired field curvature; a detecting section configured to detect an arrangement position of the distal end portion that is imaged by the imaging section to be displayed in the display section; a calculating mechanism having a calculating section configured to calculate a relative distance from a distal end of the imaging section to the distal end portion from the arrangement position detected by the detecting section; a field curvature information acquiring mechanism having a field curvature information acquiring section configured to acquire field curvature information of the taken image, wherein the field curvature information indicates the image distortion of the taken image; and an adjusting mechanism having an adjustment section configured to adjust a ratio of an operation amount of the bending operating section and a driving amount of the bending driving section based on the relative distance calculated by the calculating section, and based on the field curvature information acquired by the field curvature information acquiring section. a treatment instrument distal end movement control section having: an endoscope treatment instrument having a bending portion bendable in a desired direction and a distal end portion that is directly or indirectly coupled with the bending portion and has a treatment instrument configured to give a diseased part a treatment; a bending driving section configured to drive the bending portion to bend; and a bending operating section configured to operate the bending driving section to bend the bending portion, wherein an endoscope treatment instrument having a bending portion bendable in a desired direction and a distal end portion that is directly or indirectly coupled with the bending portion and has a treatment instrument configured to give a diseased part a treatment; a bending driving section configured to drive the bending portion to bend; and a bending operating section configured to operate the bending driving section to bend the bending portion, wherein the manipulator operation system further comprises an imaging mechanism having an imaging section that includes an optical system having a desired field curvature, configured to image the distal end portion and the bending portion by using the optical system, and provided separately from the endoscope treatment instrument, wherein the desired field curvature of the optical system results in an image distortion of a taken image that is taken by the imaging section and has the desired field curvature; an observing mechanism having a display section configured to display as an observation image the taken image that is taken by the imaging section and has the desired field curvature; a detecting section configured to detect an arrangement position of the distal end portion that is imaged by the imaging section to be displayed in the display section; a calculating mechanism having a calculating section configured to calculate a relative distance from a distal end of the imaging section to the distal end portion from the arrangement position detected by the detecting section; a field curvature information acquiring mechanism having a field curvature information acquiring section configured to acquire field curvature information of the taken image, wherein the field curvature information indicates the image distortion of the taken image; and an adjusting mechanism having an adjustment section configured to adjust a ratio of an operation amount of the bending operating section and a driving amount of the bending driving section based on the relative distance calculated by the calculating section, and based on the field curvature information acquired by the field curvature information acquiring section.