A lane departure warning device suitable to detect a position of a marking line of a lane where an own vehicle is traveling, to predict a possibility that the own vehicle will depart from the lane, and to provide a warning if the possibility of the departure is high, the lane departure warning device comprising: a marking line detection section suitable to detect the position of the marking line (31, 32) based on image information acquired from an image pickup device mounted on the own vehicle; a distance estimation section suitable to estimate a distance from a predetermined part of the own vehicle to the marking line (31, 32); a required time estimation section suitable to estimate a time required for the own vehicle to depart from the lane; a vehicle behavior estimation section suitable to estimate a steering amount of the own vehicle toward a center of the lane or amount correlating with the steering amount based on a parameter for expressing a vehicle behavior of at least one of a steering angle, a yaw rate and a lateral acceleration; a departure possibility determination unit suitable to determine whether or not the possibility that the own vehicle will depart from the lane is high based on the distance from the own vehicle to the marking line (31, 32) that is estimated by the distance estimation section, the time required for the own vehicle to depart from the lane that is estimated by the required time estimation section, and the steering amount or the amount correlating with the steering amount that is estimated by the vehicle behavior estimation section; and a warning generator suitable to provide a warning if it is determined by the determination unit that the possibility that the own vehicle will depart from the lane is high, characterized in that if it is determined that the steering amount of the own vehicle toward the center of the lane or the amount correlating with the steering amount that is estimated by the vehicle behavior estimation section is equal to a predetermined threshold value for steering amount determination or more, the departure possibility determination unit compares the distance from the own vehicle to the marking line (31, 32) that is estimated by the distance estimation section to a threshold value for distance determination predetermined for the distance, so as to determine whether or not the possibility that the own vehicle will depart from the lane is high. a marking line detection section suitable to detect the position of the marking line (31, 32) based on image information acquired from an image pickup device mounted on the own vehicle; a distance estimation section suitable to estimate a distance from a predetermined part of the own vehicle to the marking line (31, 32); a required time estimation section suitable to estimate a time required for the own vehicle to depart from the lane; a vehicle behavior estimation section suitable to estimate a steering amount of the own vehicle toward a center of the lane or amount correlating with the steering amount based on a parameter for expressing a vehicle behavior of at least one of a steering angle, a yaw rate and a lateral acceleration; a departure possibility determination unit suitable to determine whether or not the possibility that the own vehicle will depart from the lane is high based on the distance from the own vehicle to the marking line (31, 32) that is estimated by the distance estimation section, the time required for the own vehicle to depart from the lane that is estimated by the required time estimation section, and the steering amount or the amount correlating with the steering amount that is estimated by the vehicle behavior estimation section; and a warning generator suitable to provide a warning if it is determined by the determination unit that the possibility that the own vehicle will depart from the lane is high, characterized in that if it is determined that the steering amount of the own vehicle toward the center of the lane or the amount correlating with the steering amount that is estimated by the vehicle behavior estimation section is equal to a predetermined threshold value for steering amount determination or more, the departure possibility determination unit compares the distance from the own vehicle to the marking line (31, 32) that is estimated by the distance estimation section to a threshold value for distance determination predetermined for the distance, so as to determine whether or not the possibility that the own vehicle will depart from the lane is high.