PURPOSE: To provide anti-lock brake operation that is high in precision and safety, by providing in opposition to each of front and rear and right and left vehicle wheels each control unit consisting of a stress detecting sensor, a controller and an actuator, braking, by this, respective vehicle wheels respectively and separately.

CONSTITUTION: A control unit U is composed of a stress detecting sensor μfor road surface frictional force, road surface frictional coefficient or the like, a controller C and an actuator A. Also, plural control units U are provided at respective front and rear axles 10, 20 respectively in opposition to respective right and left and front and rear vehicle wheels RF-RL at a vehicle B. In addition, the master cylinder MP of a foot brake is connected to respective actuators C through oil delivery pipes 30, and plural anti-lock brake devices ABS1-ABS4 by which respective vehicle wheels FR-RL are operated independently, are constituted. Anti-lock brake operation is provided each and separately by detecting each and separately the lock inclination of each of vehicle wheels FR-RL by means of each stress detecting sensor μ and adjusting, by this, brake pressure each and separately.