A vehicle (1) having a vehicle information acquisition unit (11) which acquires image captured by a vehicle mounted sensor (20) and a camera (21), a vehicle information transmission unit (13) which transmits vehicle information data indicating information acquired by the vehicle information acquisition unit (11) to a host computer (50), a first arithmetic processing result reception unit (14) which receives first arithmetic processing result data replied from the host computer (50), and a driving assistance unit (17) which executes driving assistance processing based on the first arithmetic processing result data, the host computer (50) has a vehicle information reception unit (52) which receives vehicle information data, a first arithmetic processing unit (53) which executes first arithmetic processing on vehicle information data, and a first arithmetic processing result transmission unit (54) which transmits first arithmetic processing result data indicating the first arithmetic processing result to the vehicle (1).