When a collision avoidance steering control start condition becomes satisfied, a driving support ECU starts a steering control to avoid a collision with a frontward vehicle. The ECU prohibits the steering control when an indicated direction by turn indications of the frontward vehicle is the same as a planned direction of the steering control. The ECU sets the start condition to a first start condition, when the turn indicators of the frontward vehicle are not indicating a turning direction. The ECU sets the start condition to a second start condition, when the indicated direction is different from the planned direction. The first and second start conditions have been set such that an inter-vehicular distance between the host vehicle and the frontward vehicle of when the second start condition can be satisfied is shorter than one of when the first start condition can be satisfied.