An object driving device includes an object, a driving unit, an image capturing unit and a processing unit. The driving unit is connected to the object. The processing unit is electrically connected to the driving unit and the image capturing unit. The processing unit controls the driving unit to drive the object to move and controls the image capturing unit to capture a plurality of initial images. The processing unit subtracts pixel data of every two adjacent initial images from each other to obtain at least one subtracted image. The processing unit determines a current image position of the object in each of the at least one subtracted image. The processing unit determines a current real position of the object according to the current image position. The processing unit controls the driving unit to drive the object to move from the current real position to a target position.