Vehicle travel control assistance system having map update function, map update server apparatus, and assistance server apparatus

A travel control assistance system for a vehicle includes assistance server apparatuses, and a map update server apparatus. The assistance server apparatuses generate data that assists in a travel control of the automobile, based on respective pieces of high-precision map data and transmit the data to the automobile. The map update server apparatus updates the high-precision map data held in the assistance server apparatuses. The high-precision map data held in the assistance server apparatuses include narrow-area high-precision map data and wide-area high-precision map data regarding a wide area including an area for the narrow-area high-precision map data. The narrow-area high-precision map data is held in the low-order assistance server apparatus. The wide-area high-precision map data is held in the high-order assistance server apparatus. The map update server apparatus updates the narrow-area high-precision map data and the wide-area high-precision map data based on common data.