A manipulator is provided with a first link, a second link, first and second differential input shafts rotatably supported on the first link, a differential output shaft rotatably supported on the second link, a differential gear mechanism for rotating the differential output shaft about two axes orthogonal to each other in accordance with the sum or difference of rotating speeds of the first and second differential input shafts, a first shaft rotational angle sensor for detecting rotational angle information of the first differential input shaft, a second shaft rotational angle sensor for detecting rotational angle information of the second differential input shaft, and a controller for detecting the reception of an external force by the first or second link based on an output signal of the first or second shaft rotational angle sensor.