NETWORK HUB DEVICE

A network hub device used for building a simple network configuration in an in-vehicle network system is provided. A network hub device (35) is coupled to a trunk network and performs input/output of a signal to/from an in-vehicle device via a plurality of device side communication ports. A signal conversion section (35a, 35b) configured to perform signal conversion between a digital control signal and an analog control signal is provided between a trunk side communication port and an analog port. A second signal conversion section (70) configured to perform signal conversion between a digital control signal and an analog control signal is provided between a digital port (49) and a predetermined in-vehicle device (353).