The driving assistance device acquires, from an autonomous driving controller that determines an action of a vehicle during autonomous driving of the vehicle, action information indicating a first action that the vehicle is caused to execute. The driving assistance device acquires, from a detector that detects a surrounding situation and a travel state of the vehicle, detection information indicating a detection result. The driving assistance device determines a second action which is executable in place of the first action, based on the detection information. The driving assistance device generates a first image representing the first action and a second image representing the second action. The driving assistance device outputs the first image and the second image to a notification device such that the first image and the second image are displayed within a fixed field of view of a driver of the vehicle.