In-vehicle communication device and in-vehicle system

An in-vehicle communication device that is connected to a first communication bus and a second communication bus and relays data between the first communication bus and the second communication bus, the in-vehicle communication device comprising:

• a first communication controller connected to the first communication bus;
• and
• a second communication controller connected to the second communication bus,
• wherein when the first communication controller has received a specific message from a first in-vehicle processing device connected to the first communication bus in a state where a communication protocol of the first communication bus and a communication protocol of the second communication bus are different, the in-vehicle communication device transmits a communication protocol switching command from the second communication controller to a second in-vehicle processing device connected to the second communication bus to switch a communication protocol setting of the second communication controller to a same communication protocol as that of the first communication bus.