Abstract: The impact sensor is mounted to the front portion of the vehicle body to operate at a high degree of responsiveness. The impact load is entered into the front frame to the bumper in such a manner that the input point of input of the impact load is offset by a given distance upwards above the vertically central line of the front frame. To a lower front end portion of the front frame is joined the cross member so as to make rigidity at the upper portion of the front frame equal to that at the lower portion thereof. The impact sensor is mounted to the front frame in such a forwards inclined state with respect to the horizontal direction of the vehicle body that the direction of the impact sensor in which the impact of the crash is sensed approaches the horizontal direction.