An automatic driving assistance apparatus includes a driving state acquirer, an own vehicle location acquirer, a traveling environment information acquirer, a branch lane determining unit, a lane change calculator, and a traveling state controller. The driving state acquirer acquires a driving state of an own vehicle. The own vehicle location acquirer acquires a location of the own vehicle. The traveling environment acquirer acquires a traveling environment in which the own vehicle is traveling. The branch lane determining unit examines whether a target travel path toward which the own vehicle travels is set to a branch lane direction. The lane change calculator obtains a deceleration start position and a lane change start position of the own vehicle. The traveling state controller controls a traveling state of the own vehicle based on the deceleration start position and the lane change start position.