1. An apparatus for estimating a position of a robot, the apparatus comprising: an image acquisition unit configured to acquire an RGB image and an infrared image having depth information, and sequentially generate a reference image serving as a reference to extract feature points and an object image that is to be compared with the reference image by matching the RGB image to the infrared image; an image processing unit configured to extract two-dimensional reference feature points from each of the reference image and the object image, match the reference feature points between the reference image and the object image, and extract at least one additional three-dimensional feature point from the two-dimensional reference feature points; and a position estimating unit configured to estimate the position of the robot from the additional feature point and optimize the estimated position of the robot.