1. A method to build a 3-dimensional grid map, comprising: acquiring one or more peripheral omni-directional images captured at different locations using first and second cameras of a stereo omni-directional camera; confirming a current 2-dimensional location using the acquired one or more peripheral omni-directional images; generating a disparity map of the acquired one or more peripheral omni-directional images; performing 3-dimensional restoration of the acquired one or more peripheral omni-directional images by using a brightness information of the disparity map; and building the 3-dimensional grid map of the periphery of the stereo omni-directional camera by combining a result of the 2-dimensional localization and a result of the 3-dimensional restoration, wherein a degree of occupation of a 3-dimensional grid is obtained using a result of the 3-dimensional restoration, and wherein if a count occupied by a voxel of the 3-dimensional grid exceeds a prescribed number, a corresponding voxel is determined to be occupied.