In this vehicle body strength control apparatus, a control unit estimates the collision energy that will be generated when a host vehicle collides or makes contact with another object based on various signals input from an external sensor and from a vehicle quantity of state sensor. At a point in time when it is determined that there is a possibility of a collision or of contact occurring between the host vehicle and another object, or, alternatively, at the point in time when a collision or contact between the host vehicle and another object is actually detected, actuators are driven in a strength mode that corresponds to the strength that it is considered is required by a strength varying device for the previously estimated collision energy to be absorbed.