Disclosed is a method for sharing input/output ports among inverters. A sharing method by a master inverter according to the present disclosure is such that data to be outputted to an output port of a slave inverter is transmitted to the slave inverter where data inputted to input port of the slave inverter is received. Furthermore, a sharing method by the slave inverter is such that data transmitted along with a request frame is outputted to an output port in case of receiving the request frame requesting use of the output port from the master inverter, where data used by the master inverter among data received from input port is transmitted to the master inverter.