A human-following robot for searching a following target when failing to track the following target includes a location estimating module configured to estimate a location of the following target based on map information and trajectory information, a search range setting module configured to set a search range of the following target based on the estimated location information and human walking pattern information, and tracking module configured to track the following target after moving to the search range. Since the robot estimates a location of a missed following target and the moves to the estimated location by utilizing map information and human walking pattern information including walking pattern data of persons in a surrounding environment, which is accumulated during a predetermined period, the following target may be detected again.