A vehicle driving support apparatus comprising: a road shape detecting unit for detecting a road shape in a preset forward area which is a predetermined area set ahead of a vehicle; a steering amount detecting unit (19, S50b) for detecting a steering amount depending on an operation amount of a steering wheel steered by a driver; an obstacle detecting unit (26, S20) for detecting an obstacle present in an obstacle detection area including at least a area rearward and sideward of the vehicle; a driver intention determining unit (S50, S120a, S120b) for determining whether the driver has an intention of lane change on the basis of the road shape detected by the road shape detecting unit and the steering amount detected by the steering amount detecting unit (19, S50b); a control start determining unit for determining that approach prevention control for supporting prevention of the vehicle from approaching to the obstacle should start, when it is determined that the driver has the intention of lane change by the driver intention determining unit (S50, S120a, S120b) and the obstacle is detected by the obstacle detecting unit (26, S20); an obstacle approach prevention control unit (S130, S140, S150) for performing the approach prevention control when the control start determining unit determines that the control should start; a detection accuracy determining unit for determining detection accuracy of the road shape by the road shape detecting unit; a start determination suppressing unit (S70, S80, S90, S110, S110b) for suppressing the determination of the control start determining unit on whether the approach prevention control should start, when the detection accuracy determined by the detection accuracy determining unit is lower than a predetermined accuracy threshold; and a predicted steering angle calculating unit for calculating a predicted steering angle which is a steering angle necessary for traveling along the road shape detected by the road shape detecting unit, wherein the steering amount detecting unit (19, S50b) detects an actual steering angle which is a steering angle of the steering wheel as the steering amount, and wherein the driver intention determining unit (S50, S120a, S120b) determines that the driver has the intention of lane change when a deviation angle between the actual steering angle detected by the steering amount detecting unit (19, S50b) and the predicted steering angle predicted by the predicted steering angle calculating unit is equal to or more than a preset deviation angle. a road shape detecting unit for detecting a road shape in a preset forward area which is a predetermined area set ahead of a vehicle; a steering amount detecting unit (19, S50b) for detecting a steering amount depending on an operation amount of a steering wheel steered by a driver; an obstacle detecting unit (26, S20) for detecting an obstacle present in an obstacle detection area including at least a area rearward and sideward of the vehicle; a driver intention determining unit (S50, S120a, S120b) for determining whether the driver has an intention of lane change on the basis of the road shape detected by the road shape detecting unit and the steering amount detected by the steering amount detecting unit (19, S50b); a control start determining unit for determining that approach prevention control for supporting prevention of the vehicle from approaching to the obstacle should start, when it is determined that the driver has the intention of lane change by the driver intention determining unit (S50, S120a, S120b) and the obstacle is detected by the obstacle detecting unit (26, S20); an obstacle approach prevention control unit (S130, S140, S150) for performing the approach prevention control when the control start determining unit determines that the control should start; a detection accuracy determining unit for determining detection accuracy of the road shape by the road shape detecting unit; a start determination suppressing unit (S70, S80, S90, S110, S110b) for suppressing the determination of the control start determining unit on whether the approach prevention control should start, when the detection accuracy determined by the detection accuracy determining unit is lower than a predetermined accuracy threshold; and a predicted steering angle calculating unit for calculating a predicted steering angle which is a steering angle necessary for traveling along the road shape detected by the road shape detecting unit, wherein the steering amount detecting unit (19, S50b) detects an actual steering angle which is a steering angle of the steering wheel as the steering amount, and wherein the driver intention determining unit (S50, S120a, S120b) determines that the driver has the intention of lane change when a deviation angle between the actual steering angle detected by the steering amount detecting unit (19, S50b) and the predicted steering angle predicted by the predicted steering angle calculating unit is equal to or more than a preset deviation angle.