To provide a steering mechanism control device that can stably and surely drive a steering mechanism regardless of a steering amount signal inputted to a steering input means.

A steering mechanism control device in a vehicle has wheels 1, 2 of three wheels or more and steering mechanisms 4 independently steerable for all the wheels. Each of drive wheels of the respective wheels 1, 2 is independently driven to travel by a traveling drive mechanism 5 including a motor 6. Each of the steering mechanisms 4 has a steering drive source 4a and is a steer-by-wire system. An integrated control means 31 for controlling the steering mechanisms 4 and the traveling drive mechanism 5 outputs a steering amount command with a given ratio with respect to a steering amount signal inputted by a steering input means 27 to the steering drive source 4a. The integrated control means 31 has a steering amount correcting means 32b that corrects the steering amount command with the given ratio outputted to the steering drive source 4a by the steering amount signal of the steering input means 21.