A method and a gateway for extending a network are disclosed. A method by which a gateway extends an EtherCAT network to a wireless network according to an embodiment of the invention includes: receiving first data from the EtherCAT network and converting the first data by a protocol conversion to second data suitable for the wireless network, and transmitting the converted second data to the wireless network, where the transmitting of the converted second data may include reducing the difference in communication speed between the EtherCAT network and the wireless network by using an internal buffer.