A lane departure prevention apparatus according to an embodiment includes a torque control section that outputs a torque control signal indicating to make an actuator generate automatic steering torque for preventing a vehicle from departing from a lane in which the vehicle is running a driver steering torque detection section that detects driver steering torque, which is applied to a steering wheel of the vehicle by a driver and a control stop determination section that determines whether or not the automatic steering torque is made zero by comparing a first cancel threshold value for determining sudden steering operation by the driver and a second cancel threshold value lower than the first cancel threshold value with the driver steering torque detected by the driver steering torque detection section. If the torque control section determines to make the automatic steering torque zero, the torque control section outputs the torque control signal so that the automatic steering torque is made zero with a predetermined torque change pattern. If the driver steering torque is the first cancel threshold value or more, the torque control section sets the torque change pattern to a pattern in which the automatic steering torque is promptly made zero. If the driver steering torque is less than the first cancel threshold and is equal to or more than the second cancel threshold, the torque control section sets the torque change pattern to a pattern in which the automatic steering torque is gradually decreased.
