An apparatus predicts a turn of a vehicle based on a picked-up image of a forward view of the vehicle. The forward view is imaged by an on-vehicle sensor to repeatedly acquire images. The acquired images include position coordinate information of a light source and information indicating whether the light source is a light source of a preceding vehicle or a light source of an oncoming vehicle. Based on such information, it is determined whether or not the light source is a light source of an oncoming vehicle newly appeared in the images and the light source is in a predetermined area near the left end or in a predetermined area near the right end in the images. When the determination result is affirmative, it is determined that there is a curve in the traveling direction of the vehicle.