Disclosed are a movable device allowing instantaneous correction of error in a moving state and an error correction method thereof. The movable device includes a drive unit that is previously set up with an allowable error and has a moving path along which detection units are installed in a line. Precise measurements are taken in advance to obtain position data of each of the detection units. Comparison is then made by the controller between instantaneous data and corresponding comparison data. When the controller determines the instantaneous data exceed the comparison data, an instantaneous correction operation is made to make the instantaneous data not exceeding the comparison data. Acceleration or deceleration may be made by the drive unit to effect such a control that when the movable piece reaches the next detection unit, the instantaneous data do not exceed the comparison data.