In order to make it possible to easily acquire device information relating to a work device, this communication system of a work machine comprises: a first communication device which can be mounted on a work device provided detachably on a vehicle body and which externally transmits device information relating to said work device as a broadcast signal; and a receiving device which has a receiving unit that can receive device information transmitted by a broadcast signal. The first communication device has a first output unit which can externally output, as device information, information that includes identification information for identifying the work device. The receiving device has a second output unit which connects to an in-vehicle network and outputs the identification information received by the receiving unit to said in-vehicle network.
