provided are a detector and a method of detecting an object using the detector . the method includes combining a first detector and a second detector in a combination scheme to form a multi - layer combination detector , the second detector being of a type different from that of the first detector , processing a binary classification detection with respect to an inputted sample starting from an uppermost layer detector , allowing a sample of an object detected from a current layer to approach a lower layer , while rejecting a sample of a non - object detected from the current layer whereby the rejected non - object may not approach the lower layer , and outputting a sample passing through all layers as a detected object .