1. An object detection apparatus, using at least one processing circuit, for detecting an object in an image capturing area based on parallax information generated from a plurality of images captured by a plurality of cameras, the object detection apparatus comprising: a processor configured to, generate vertical-direction parallax histogram information based on the parallax information, the vertical-direction parallax histogram information indicating a frequency profile of parallax values in each of vertical row areas in a captured image, the vertical row area preparable by dividing the captured image in a plurality of areas in a left-right direction, extract, among parallax values having frequency exceeding a given frequency threshold, a group of pixels having parallax values existing within proximity of a given parallax value and having a pixel-to-pixel interval in an image left-to-right direction within a given range, as an object image area that includes an object for display, based on the vertical-direction parallax histogram information, calculate a width and a height of the object based on the extracted object image area, compute data corresponding to an actual horizontal size and vertical size of the object based on the parallax information at the object image area and the calculated width and height of the object, and determine a type of the object based on the computed data by, determining whether the actual horizontal size and vertical size are within a threshold width and a threshold height for one of a plurality of types of objects, computing, for each of a plurality of blocks, a weighted feature value between the object image area of a respective one of the plurality of blocks and a luminance image, and computing an evaluation value based on the weighted feature values for each of the plurality of blocks.