A parking assist device detecting a parking stall line from an image, which is captured by a capturing portion; setting a parking target position on the basis of the parking stall line; and assisting the vehicle to travel to the parking target position; the parking assist device includes a vehicle detecting portion for detecting a movement of the vehicle, a memorizing portion for memorizing the movement detected by the vehicle detecting portion, as a vehicle moving trajectory, a temporary parking target position estimating portion for assuming a temporary parking target position on the basis of variations of the vehicle moving trajectory, which has been memorized by the memorizing portion, and a parking stall line searching area setting portion for setting a parking stall line searching area, within which a parking stall line is searched on the basis of the temporary parking target position.