A method for controlling a manipulator includes a joint structure portion having one or more joints connected to a distal end of an insertion portion, a power transmission member inserted into the insertion portion to transmit driving force to the joint structure portion, and a driving portion that drives the power transmission member and which is guided to an application site by being inserted into the channel member. When the manipulator is operated in an insertion control mode for inserting the joint structure portion into the channel member, the method includes detecting a load amount generated in the power transmission member or the driving portion and creating a bending state in which the joint structure portion follows the channel member by controlling a driving amount of the power transmission member by the driving portion such that the load amount becomes within a predetermined target control range.
