A fire alarm spreading system includes a robot cleaner for generating fire alarm data when smoke is detected while patrolling a specific area and transmitting the fire alarm data; and a wireless communication base station for receiving the fire alarm data transmitted from the robot cleaner and transmitting the received fire alarm data to a pre-set fire center. When a fire breaks out in a specific space (e.g., in a house), the mobile robot such as the robot cleaner detects the fire (smoke) and generates a fire alarm tone. Thus, the fire can be quickly detected and people can evacuate from the fire-generated area, reducing casualty.