A moving robot and its operation method are disclosed. The moving robot includes a moving body/object sensing unit that senses a movement of a human body within a certain distance, a traveling unit that controls a traveling speed and direction, and a controller that outputs a control signal for controlling the traveling speed according to pre-set data to the traveling unit. In a state that the moving robot performs a cleaning operation while moving its locations, when a movement of a human body is sensed by the moving body/object sensing unit, the traveling speed is reduced to allow the user to easily control the external operation, and the efficiency can be increased by utilizing the moving body/object sensing unit for operations of different modes.