Abstract: A control device for a mobile body makes it possible to smoothly correct the deviation of an actual posture of a base body of a mobile body, which travels with the base body thereof moving up and down, from a desired posture of the base body while restraining an overshoot or an undershoot from occurring. To determine a required manipulated variable according to a feedback control law in order to converge a state amount deviation related to the posture of the base body of the mobile body to zero, the feedback gain of the feedback control law is determined by using the time series in a period from current time to predetermined time in the future in the time series of a desired inertial force of the mobile body or the base body. The required manipulated variable is determined by the calculation of the feedback control law on the basis of the determined feedback gain and an observed value of the state amount deviation.