An in-lane drive assist device controls a turning amount of a turning unit that is mechanically detached from a steering unit-based on a steering amount of a steering unit when a lane deviation is determined to be absent. The in-lane drive assist device controls the turning amount based on a drive assist turning amount for generating a yaw moment to return a vehicle into a lane while the steering reaction force applied to the steering unit is controlled based on a target steering reaction force corresponding to a steering reaction force characteristic that is set so that a self-aligning torque increases as the steering reaction force increases when a lane deviation is determined to be present, and the steering reaction force characteristic is offset in a direction in which an absolute value of the steering reaction force increases as a lateral position of the vehicle approaches a white line.