WARNING DEVICE AND TRAVEL CONTROL DEVICE

A warning device includes a distance acquisition unit (21) that acquires a lane width direction distance between two lane boundary lines of a driving lane and a vehicle; a speed acquisition unit (22) that acquires a lane width direction speed of the vehicle toward the lane boundary lines; a safety threshold setting unit (27) that sets a safety threshold for allowing that the lower the lane width direction speed is toward the lane boundary lines, the smaller the lane width direction distance is; and a warning unit (28) that warns a driver of the vehicle when the lane width direction distance is smaller than the safety threshold, wherein the safety threshold setting unit (27) sets the safety threshold based on a history of the lane width direction distance and the lane width direction speed for a traveling environment of the vehicle.