A module type node apparatus for packet communication of this invention includes an extension module for executing predetermined processing and a node apparatus main body for forwarding packet data to the extension module, the extension module including a memory for storing connectivity authentication data, and a module controller for transmitting the connectivity authentication data stored in the memory to the node apparatus main body for packet communication when the connectivity authentication data is requested from the node apparatus main body for packet communication, the node apparatus main body for packet communication being characterized by further including a connectivity authentication unit for authenticating permission of connection of the extension module based on the connectivity authentication data received from the extension module, and a connection controller for receiving the packet data from the extension module when the connectivity authentication unit permits the connection.