1. An apparatus for providing an activity recognition based application service, comprising; an image receiving module that collects a depth image provided from a camera and transfers the depth image to a human body detection module; the human body detection module that receives the depth image from the image receiving module to detect a position of a human body from the depth image and transfers information of the position to an activity recognition module; and the activity recognition module that receives the information of the position from the human body detection module to recognize an action of the human body on the basis of a comparison between a feature of a three-dimensional action volume extracted from the human body and a learning feature of a previously learned action model.