This automatic driving assistance device automatically performs least a part of vehicle control including steering, braking, and acceleration and deceleration within a predetermined travel section. The automatic driving assistance device includes: a switching section determination unit that determines, in the travel section, a section in which a first load that is based on a road shape or a road structure becomes equal to or less than a predetermined threshold as a switching section in which the at least a part of the vehicle control is switched from automatic driving to manual driving; a driving action planning unit that, when the vehicle enters the determined switching section, generates an automatic driving action plan so that a second load that is based on a travel situation of nearby vehicles around the vehicle is reduced; and a driving switching unit that ends automatic driving that is based on the automatic driving action plan and switches the automatic driving to the manual driving.