To provide a positioning device and method capable of correcting a position update error of a measured value of a wheel speed sensor unit resulting from a slip, and updating the position of a moving body with high precision.

When the position of the moving body can be updated by a positioning result from a GPS receiver 2, the relation between a slip ratio Sr and an acceleration Aw determined from information of the sensor is predetermined from information acquired from the wheel speed sensor 1 and the receiver 2. When the position of the moving body can not be updated by the positioning result from the receiver 2, a slip ratio Sr corresponding to a found acceleration Aw' is calculated from the above relation. By using this slip ratio Sr and correcting the measured value of the wheel speed sensor unit, and performing a position update by using this corrected value, the precision of updating of the position of the moving body can be raised.