An operation support device includes a manipulation input unit that outputs a manipulation command in accordance with an input from an operator, and a motion unit that causes a surgical instrument to move in accordance with the manipulation command. The manipulation input unit includes an object-to-be-detected that is gripped by the operator and a detection device that detects the object-to-be-detected. The object-to-be-detected includes a body part that has a first marker, which is detected by the detection device, disposed thereon, a manipulation part that is disposed in the body part and that is manipulated by the operator, and a second marker that is disposed in at least one of the body part and the manipulation part.