A lane boundary line recognition apparatus acquires an image. Based on edge points extracted from the image, a lane boundary line candidate is extracted, and a lane boundary line probability thereof is calculated. A lane boundary line candidate of which the lane boundary line probability exceeds a threshold is recognized. As the threshold, a first threshold, larger than a second threshold in normal mode, is set when a first condition is met and also a second condition is met. The first condition is that a single lane boundary line is recognized on a roadside side of a lane in which the own vehicle is traveling, and a composite lane boundary line is recognized on a side opposite the roadside side. The second condition is that a state in which a lane boundary line cannot be recognized on at least the opposite side continues for a predetermined amount of time.