A cruise control device 10 is applied to a vehicle in which an imaging device 21 is mounted. The cruise control device 10 includes: a white line recognition unit 11 which recognizes a white line 61 as a lane boundary that defines an own lane 63 that is a travel lane of an own vehicle 50, on the basis of images acquired by the imaging device 21; and a cutting-in/deviation determination unit 12 which performs cutting-in determination and deviation determination, in which the forward vehicle traveling on an adjacent lane 64 is determined to be a cutting-in vehicle that cuts into the own lane, and the forward vehicle traveling on the own lane is determined to be a deviating vehicle that deviates from the own lane on the basis of a relative position with respect to the white line in a vehicle width direction of a forward vehicle 51.