The invention relates to a technique for reducing computation time for force vector calculation. A force vector reconstruction method that uses an optical tactile sensor, comprises a step for obtaining a marker image by taking an image of behavior of colored markers when an object contacts a contact surface of an elastic body, a step of obtaining information relating to the marker behavior from the marker image, the information being more than the number of force vectors to be obtained, and a step of obtaining force vectors as outputs by inputting information relating to the obtained marker behavior to a transfer function. The step of obtaining force vectors comprises calculating force vectors using only information relating to behavior of markers neighboring region A1 of a position A where it is desired to obtain force vectors.