1. A three-dimensional map-generating apparatus, comprising: an odometer detecting a pose of a mobile robot; a distance-measuring sensor, including a light source module to emit light upward relative to a movement direction of the mobile robot and a camera module to capture an image formed by the light as reflected from an obstacle, measuring a distance to the obstacle for the mobile robot using the captured image; and a map-generating unit generating a three-dimensional map using the distance measured by the distance-measuring sensor while changing the pose of the mobile robot.