When a stage moves, the position of the stage is detected by an interferometer, and a control unit controls the position of the stage while monitoring the output of the interferometer. Thus, the control unit effects positioning of the stage. In addition, the control unit calculates the square root of an arithmetic mean of the square of an error between target and present positions of the stage on the basis of the output of the interferometer, and estimates an amount of vibration of the stage on the basis of the result of the calculation, thereby enabling vibration characteristics to be quantitatively evaluated to a certain extent when the damping of vibration is rapid immediately after positioning, or when the damping is gentle or almost zero.