Lane keeping assist device and lane keeping assist method

Here the vehicle is traveling lane lateral displacement reference position L in the width direction respectively transverse direction right and left from the center of which sets the LXL, LXR. And feedback-controls at least if the right and left sides of the lateral displacement reference positions LXL, LXR character within the vehicle position, yaw characters each deviation is smaller vehicle. Further, the driving lane if the right and left sides of the lateral displacement reference positions LXL, LXR-party vehicle outside than about the middle, and the feedback control is the angular deviation and lateral displacement deviation becomes small.