When detecting a face included in an input image by use of at least two inclinations of the face to be detected, a first detection process is performed if the inclination of the face to be detected corresponds to a first inclination where a relatively high face detection probability is expected, and a second detection process having a relatively low face detection probability and a relatively short processing time compared with the first detection process is performed if the inclination of the face to be detected is other than the first inclination. When an input image is scanned to enable the change in face detection processes according to the position of the face to be detected, a different detection process is used according to the face detection probability of the position of the face to be detected.