A medical manipulator system includes: a manipulator having a treating portion at a distal end thereof; an endoscope configured to capture an image showing a state of the treating portion performing treatment; an external-force detecting means for generating data on an external force exerted on the manipulator; a display for an operator; and a controller comprising a hardware including at least one processor. The at least one processor is configured to: receive the data from the external-force detecting means; generate an auxiliary image in which a display form thereof is changed on the basis of the data; receive the image from the endoscope; determine a display position of the auxiliary image in the image on the basis of the data; generate a signal being capable to display a composited image which is superimposed on the auxiliary image on the image on the basis of the display position; and transmit the signal to the display.