To estimate the posture of an occupant without using a special sensor, thereby achieving a favorable control.

An inverted mobile object 201 includes: a wheel 106; a platform 101; a unit 108 for estimating the posture of the occupant, which estimates the posture of the occupant in a vertical direction of the occupant 102 as an estimate value of the posture of the occupant based on an inclined angle of the platform 101 in the vertical direction, a rotation angle of the wheel 106, a rotary drive torque command of the wheel 106, a mass of the wheel 106, a radius of the wheel 106, an inertia moment about the rotation axis of the wheel 106, a mass of the occupant 202, and a distance between the platform 101 and the center of gravity of the occupant 102; and a controller 103 for controlling the rotary drive of the wheel 106 based on the inclined angle of the platform 101 in the vertical direction, the estimated value of the posture of the occupant thus estimated and obtained by the unit 108, and the rotation angle of the wheel 106.