1. An apparatus for detecting an object using a multi-directional integral image, comprising: an area segmentation unit configured to place windows having a size of x*y on a full image having w*h pixels so that they overlap each other at their edges, thereby segmenting the full image into a single area, a double area and a quadruple area; an integral image calculation unit configured to calculate a single directional integral image for the single area and calculate multi-directional integral images for the double and quadruple areas; and an object detection unit configured to detect an object for the full image using the single directional integral image and the multi-directional integral images; wherein each of w and h is one of natural numbers, and each of x and y is one of natural numbers, wherein x and y are smaller than w and h, respectively.