To provide a controller adjusting and controlling a temperature of vehicle axle assembly.

The controller is characterized in that a conduit is connected to a heating/cooling fluid circuit of internal combustion engine to keep heating/cooling liquid circulated to axle assembly through an inlet conduit, which passes through a wall of the axle assembly and terminates at a heat exchanger, in that the heat exchanger is arranged beneath a stagnant spot formed by a lubricating liquid of the axle assembly to make coolant heat the lubricating liquid during vehicle first stage operation and low working speed at the time of starting condition at low temperature, and cool the lubricating liquid when the vehicle operates at high temperature and high speed, and in that the heating/cooling liquid is returned to the cooling liquid circuit through an outlet conduit.