A lane changing support apparatus includes a plurality of radar sensors and a driving support ECU. The driving support ECU determines whether or not a target object is highly likely to have entered a blind spot area of the radar sensors based on fusion target object information, when starting an extrapolation process of the fusion target object. When the driving support ECU determines that the fusion target object is highly likely to have entered the blind spot, the driving support ECU prohibits the lane changing support control to a lane in the side of this blind spot area.