A communication device (202) for performing communication with other vehicle through a wireless communication network which performs communication by switching a communication state to a standby state or to a connecting state, and a state setting means (208) for selectively setting a state of the communication device to the standby state or to the connecting state are provided, wherein the state setting means judges whether or not at least one predetermined condition is met based on the information on an own vehicle and/or the information on other vehicle, sets the communication device to the connecting state when the condition is met, and sets the communication device to the standby state provided that the condition is not met.