1. An object image detection device for detecting one or more object images from an input image, comprising: an image block generation unit configured to generate a plurality of image blocks from the input image for detecting the object images; an image classification unit configured to determine whether each of the image blocks includes one or more of the object images by using one or more features of the object images, and acquire the image blocks including the object images to be object image candidates; and a detection unit configured to sequentially detect the object images from the object image candidates; wherein the image classification unit acquires the object image candidates based on a relative positional relationship between the image blocks and already-acquired object image candidates.