Provided is a remote broadcast system including an audio amplifier activation device configured to turn on when a level of input sound via a smartphone mobile unit exceeds a threshold, a power source for an audio amplifier configured to amplify a signal of the input sound into a broadcast audio signal, and output the broadcast audio signal to a broadcast loudspeaker, the audio amplifier activation device being configured also to turnoff the power source for the audio amplifier when the level of the input sound remains lower than the threshold for a predetermined time period. A broadcaster carrying a smartphone base unit can select a smartphone mobile station via the smartphone base unit, and establish a communication link between the smartphone base unit and the smartphone mobile station. With this, the broadcaster is allowed to broadcast evacuation guidance information even while evacuating.