External environment recognition apparatus

An external environment recognition apparatus includes an in-vehicle detector and a microprocessor. The microprocessor is configured to perform: recognizing a surface of the road and a three-dimensional object on the road for each frame as the road surface information based on a three-dimensional point cloud data including distance information for every one of a plurality of detection points in a matrix shape acquired in every frame by the in-vehicle detector; determining an interval of detection points of the three-dimensional point cloud data as a scanning angular resolution of the electromagnetic wave based on a size of a predetermined three-dimensional object and a distance to the predetermined three-dimensional object; and taking a predetermined avoidance measure so that at least one of the scanning angular resolution and a number of detection points corresponding to the interval of detection points does not exceed a predetermined limit value.