1. An augmented reality device based on recognition of a spatial structure, the augmented reality device comprising: a memory for storing one or more computer-executable units which are executed by a processor, wherein the one or more executable units comprising: a point cloud normal vector extracting unit extracting a normal vector for a point cloud from image data input from a camera; a plane object segmenting unit segmenting a plane in the image data by using the extracted normal vector; a representative plane selecting unit selecting a representative plane among the segmented planes, wherein the representative plane includes a bottom plane, a rear wall, and a ceiling plane, wherein the representative plane selecting unit selects the representative plane by using a contextual knowledge of the camera and an indoor space configuration, wherein in the contextual knowledge for selecting the rear wall plane among the representative planes, the normal vector of the bottom plane and the wall plane among the representative planes are vertical to each other, the normal vector of the ceiling plane and the wall plane among the representative planes are vertical to each other, and the rear wall plane is spaced apart from the camera by a predetermined interval; a spatial structure extracting unit recognizing a spatial structure by using the representative plane; and a virtual object matching unit matching a virtual object in the recognized spatial structure.