An estimation device includes an information acquisition unit, a detection determination unit, a direction determination unit, and a direction estimation unit. When an object is a first-time detected object, the direction determination unit determines whether a relative direction acquired by the information acquisition unit is a direction toward an own vehicle. When the relative direction acquired by the information acquisition unit is a direction toward the own vehicle, the direction estimation unit estimates that a direction predetermined according to an object position acquired by the information acquisition unit is the movement direction of the object.