A polling communication system includes a main station and a plurality of sub stations connected to the main station. The main station includes an address control part and a polling control part. The address control part divides a predetermined polling cycle into a plurality of kinds of polling intervals each having a different number of times of polling, and holds addresses of polling target sub stations corresponding to the respective polling intervals. The polling control part switches the polling intervals and changes the addresses in the address control part according to states of the sub stations. Each of the sub stations includes another polling control part that sends a response when the sub station is polled by the main station.