We have developed the person following robot "ApriAttenda™" . This robot can accompany a person using vision based target detection and avoid obstacles with ultrasonic sensors while following the person. The robot first identifies an individual with its image processing system by detecting a person's region and recognizing the registered color and texture of his/her clothes. Usually, the person following robot has to detect and recognize the specified person and calculate his/her position in a complicated real-life environment of fixed objects and moving people. Our newly developed algorithm allows the robot to extract a particular individual from a cluttered background, and to find and reconnect with the person if it loses visual contact. Tracking people with stereo vision was realized by systematizing visual and motion control with a robust algorithm that utilizes various characteristics of the image data. The developed algorithm uses several analyses to extract information on the distance to each feature point, speed of target, color and texture of clothes for a stable tracking in many situations including changes of view due to self motion, shifts in lighting and objects similar to the target. The person following robot ApriAttenda™ has been exhibited at Aichi EXPO 2005, and its robust functions and smooth person following capability were successfully demonstrated.