A map information processing apparatus includes a map information storage unit 111 for storing map information which is separated into multiple layers, a layer-to-be-updated-with-addition determination processing unit 118 for determining one or more layers which are to be updated with addition of an unregistered road which has been detected during travel of a vehicle, and an unregistered road adding and updating unit 117 for adding the unregistered road to the map information storage unit to update the map information with the addition being aimed at the one or more layers determined by the layer-to-be-updated-with-addition determination processing unit.