A cruise control device has a white line recognition unit recognizing a white line defining a lane having the own vehicle, based on an image captured by an image capturing device and a lane entering and leaving determination unit carrying out lane entering determination and lane leaving determination of the own vehicle with respect to a preceding vehicle traveling ahead of the own vehicle based on the relative position of the own vehicle in the vehicle width direction with respect to the white line. In the lane entering determination and lane leaving determination, a preceding vehicle on the lane to which the own vehicle is moving is determined to be an entering lane vehicle whose lane the own vehicle is entering, and a preceding vehicle on the lane from which the own vehicle is moving is determined to be a leaving lane vehicle whose lane the own vehicle is leaving.