An apparatus and method for detecting friction characteristics are disclosed, in which a wheel resonant system includes a vehicle body, a road surface and at least a wheel. A braking force control system exerts a braking force on the wheel. A resonant component detector determines a resonant gain providing the ratio between the amplitude of predetermined frequency component of the braking force and that of the wheel velocity and detects the ratio of the resonant gain to a present reference gain, a deviation calculator calculates the deviation between this ratio and unity, a PI controller controls the braking force control system in such a manner that the deviation coincides with zero, and a friction characteristics detector detects the friction characteristics on the basis of the braking force. When the friction force is made to approach a peak value by increasing the braking force, the resonant characteristics undergo a change thereby to reduce the resonant gain. By controlling the braking force in such a manner that the deviation coincides with zero, therefore, the friction characteristics are held at a peak value. This braking force reflects the friction characteristics, and therefore the friction characteristics between the road surface and the wheel can be accurately detected according to the relative magnitude of the braking force.