A lane departure prevention device includes departure prevention control means that performs control to prevent deviation from a lane based on a result of detection means such as sensors and a camera, driver's intention determination means that determines driver's steering intention and actuator activation limiting means that limits activation of an actuator based on the driver's steering intention from the driver's intention determination means. The driver's intention determination means calculates a variation ΔTh in the steering torque detected and a variation ΔTs in the control command value to a steering actuator, and determines that, when |ΔTh|−|ΔTs| is a threshold or more, driver's operational intention is present and limits the activation of the departure prevention control. This can avoid the interruption of departure prevention control in response to activation of an actuator for lane departure avoidance that a driver does not intend because of erroneous detection that a driver intends as such.