1. A system for controlling a legged humanoid mobile robot having a body, a plurality of legs and arms each connected to the body, a leg actuator for driving the legs and an arm actuator for driving the arms, comprising: a map database configured to store a map of environmental space where the robot moves; an operation controller configured to identify one of human beings to be conducted, and control operation of at least the leg actuator to conduct the identified human being to a destination in the space along a route determined based on the map, while keeping a predetermined distance from the human being; a head actuator configured to drive a head connected to the body; and an utterance generator configured to generate utterance, wherein the operation controller controls operation of the leg actuator to conduct the human being at a moving speed that is in pace with a walking speed of the human being, controls operation of the head actuator to turn the head back so as to see the human being and operation of the leg actuator to decrease the moving speed when the distance from the human being increases during conducting, controls operation of the utterance generator to utter to the human being by selecting words according to a remaining of distance, and controls at least operation of the utterance generator to utter to the human being in order to look for the human being if the human being is lost during the conducting.