To provide a load surface conditions detector for a vehicle capable of directly and accurately detecting a road surface on which the vehicle is running based on the coefficient of friction of the road surface reflecting the conditions of the road surface and the behavior of the vehicle at that time by providing a specified driving force or a braking force to each wheel according to the running conditions of the vehicle.

This road surface conditions detector comprises a μ calculation means 45 for calculating the coefficient of friction μ of the road surface for each wheel, a μs calculation means 46 for calculating the coefficient of friction μ of the road surface in lateral direction for each wheel, running conditions determination means 47 for varying the control mode of the wheels by determining the present behavior of the vehicle, a driving force control means 48 for controlling a throttle control motor 11 according to the determined behavior of the vehicle, a braking force control means for controlling an electromagnetic control valve 6 according the determined behavior of the vehicle, and road surface conditions determination means 50 for determining the conditions of the running road surface based on the coefficient of friction μc of the road surface or the coefficient of friction μsc of the road surface in lateral direction for each wheel during the control.