A method and apparatus for detecting an object are provided. The method calculates a feature value based on features extracted from an input image by using a classifier of an ith stage, compares the calculated feature value with a first threshold value of the ith stage, compares the feature value with a second threshold value of the ith stage according to a result of the comparison between the feature value and the first threshold value of the ith stage, and jumps to a classifier of an i+2th stage according to a result of the comparison between the feature value and the second threshold value of the ith stage. By doing so, the method can avoid repeated calculations and can rapidly detect the object in the input image.