A lane departure prevention apparatus (17) has: a departure preventing device (172) for preventing a vehicle (1) from departing from a driving lane by controlling at least one of a steering apparatus (142) and a braking apparatus (13) selected on the basis of a state of the vehicle, when it is determined that the vehicle may depart from the driving lane; and a determining device for determining whether or not an abnormality condition that it is difficult for a person to normally drive the vehicle is satisfied, the departure preventing device prevents the vehicle from departing from the driving lane by controlling the braking apparatus even if the state of the vehicle is not a predetermined state in which the departure preventing device should prevent the vehicle from departing from the driving lane by controlling the braking apparatus, when it is determined that the abnormality condition is satisfied.