When a deceleration intention detector detects that an occupant has apprehension about a condition ahead of his own vehicle and attempts to decelerate the own vehicle, a detection area setter enlarges a detection area in which a control object is detected, upon a command from a control object determinator. Therefore, a new control object such as a cutting-in vehicle can be more reliably detected in accordance with an increase in an amount of attention which the occupant pays to the condition ahead of the own vehicle. As a result, a vehicle controller changes a vehicle control content of the own vehicle, thereby performing an appropriate vehicle control with respect to the newly detected control object to eliminate a sense of discomfort of the occupant.