To achieve the reduction of collision damage while preventing the malfunction of a collision damage reduction device.

A collision time t required up to collision with an obstacle is arithmetically operated, based on a distance L up to an obstacle positioned in the forwarding direction of a vehicle and the relative velocity V to the obstacle (S1 and S2). When the collision time t becomes a threshold value or lower which regulates brake operation timing (S8), a brake is operated and fuel supply is stopped (S9). At this time, a threshold value is reduced by only a predetermined value (S6 and S7), when a driver of the vehicle intends to accelerate the vehicle (S3), when it is within a prescribed time since the transmission is shifted down by the driver (S4), and when a winker is operating (S5). This structure prevents sudden brake operation even if the distance to the obstacle is shortened temporarily when traffic lane changing operation is carried out with acceleration, so that instability by the change of vehicle attitude and a collision by a following rear-side vehicle can be suppressed.