An object detection apparatus that detects an object to be detected captured in a determination image according to a feature amount of the object to be detected preliminarily learned by the use of a learning image, the object detection apparatus including a detector causing strong classifiers to operate in order of lower classification accuracy, continuing processing when the strong classifier has determined that the object to be detected is captured in the determination image, and determining that the object to be detected has not been detected without causing the strong classifier having classification accuracy higher than the aforementioned strong classifier to operate, when the strong classifier has determined that the object to be detected is not captured in the determination image, wherein the strong classifier inputs a classification result of the strong classifier having classification accuracy lower than the aforementioned strong classifier and determines whether the object to be detected is captured or not in the determination image according to the plurality of estimation values and the input classification result.