1. An apparatus for estimating a pose of a mobile robot, comprising: an odometer which detects a variation in the pose of a mobile robot; a feature-processing module which extracts at least one feature from an upward image captured by the mobile robot; and a particle filter module which determines current poses and weights of a plurality of particles by applying the mobile robot pose variation detected by the odometer and the feature extracted by the feature-processing module to previous poses and weights of the particles.