A first
pedestrian judging unit judges, on the basis of the size and motion state of a target three-dimensional object, whether the object is a
pedestrian. A second
pedestrian judging unit judges, on the basis of shape data on the object, whether the object is a pedestrian. A pedestrian judging unit finally determines that the object is a pedestrian when both the first and second pedestrian judging units judge the object as a pedestrian, when the second pedestrian judging unit judges the object as a pedestrian, when the first pedestrian judging unit judges the object as a pedestrian and a result of this judgment is held for a preset period, or when the first pedestrian judging unit judges the object as a pedestrian in a current judgment operation and the second pedestrian judging unit judged the object as a pedestrian in the previous judging operation.