1. An action recognition method using a computer for acquiring image data generated by capturing an image including a face of a human and outputting action information representing an action content of the human captured in the image data, the action recognition method comprising: specifying a first image region including a face portion of the human from the image data; acquiring skin-color information peculiar to the human from pixel values of the first image region; specifying at least one second image region including a predetermined portion of a body of the human from the image data except for the first image region based on the skin-color information, wherein the specifying the at least one second image region comprises obtaining a center of gravity of the skin-color information; and outputting the action information representing the action content of the human based on position relation between the specified first image region and the specified second image region, wherein the specifying the at least one second image region further comprises moving a search region until a distance between a newly obtained center of gravity and a previously obtained center of gravity of the search region is equal to or lower than a predetermined value.