A lane keeping assist apparatus is disclosed which includes a lane detecting part that detects a lane in which a vehicle travels; an actuator that generates a force for changing an orientation of the vehicle; and a controller that operates the actuator such that the vehicle travels within the lane under a situation where a lane keeping assist function is in its ON state, wherein under a situation where the controller is operating the actuator, the controller determines whether an operation amount of the actuator is less than a predetermined first threshold, and prevents an output of operation information if it determines that the operation amount of the actuator is less than the predetermined first threshold, the operation information representing an operated state of the actuator.