Evaluation values regarding a change in velocity of an object at coordinates of a detection surface are calculated on the basis of a series of coordinate data of the same object, and it is determined whether there is an error in each coordinate data on the basis of the evaluation values. In a case in which an extreme change in a velocity of the object occurs due to an influence of noise or the like, it is possible to accurately determine an error of the coordinate data on the basis of the evaluation values. Since the coordinate data in which it is determined that there is an error is corrected with data indicating the same coordinate P as that of coordinate data immediately before such coordinate data, the error of the detection result of the coordinates can be effectively reduced.