In an object detection apparatus, a captured image of a scene around a host vehicle, information indicating a travel state of the host vehicle, and information indicating a surrounding situation around the host vehicle are obtained; risk areas in each of which an object is likely to exist, and area risk degrees of the risk areas are estimated based on the obtained information; posture risk degrees of respective postures are estimated based on a relation between each of the risk areas and the postures of the object assumed to exist in the risk area; a window image is extracted from a search range in the captured image, which corresponds to each of the risk areas, according to descending order of overall risk degrees; and it is identified whether the window image is an image showing the object, by comparing an identification model with the window image.