PURPOSE: To control the height to an optimum in accordance with the operating conditions by detecting the traveling conditions of the vehicle, the open/close condition of the doors, and the operation of a height vertically shifting device, so that the weighting factor to be used for obtaining a weighted mean by adding weight to the detected heights of respective wheels can be set or changed.

CONSTITUTION: On the basis of the respective information of a traveling condition detecting means G, a door open/close condition detecting means H, and an operating condition detecting means I of vertically shifting devices C which have been provided to respective wheels A, B, a factor setting means J sets or changes the weighting factor which is used by a weighted-mean calculating means E for obtaining a weighted mean. When the heights detected by height detecting means D of respective wheels are subjected to weighed-mean calculation by the weight-mean calculating means E, this changed set factor is used. As a result, a drive control means F controls respective vertically shifting devices C. By this constitution, the height can be controlled to an optimum in accordance with the operating conditions.