A cruise control apparatus can control a host vehicle to run with a fixed separation from a preceding vehicle when such a preceding vehicle is detected based on received radar signals and to run at a preset fixed speed when no preceding vehicle is detected. The cruise control apparatus is configured to respond to one of a set of predetermined actions by the vehicle driver, which indicate an intention to change the vehicle speed, by making it easier or more difficult for a preceding vehicle to be detected, in accordance with whether the indicated intention may signify that an actual preceding vehicle is not being detected or may signify that a non-existent preceding vehicle is being detected and that the host vehicle speed has been reduced accordingly. Improved performance is thereby achieved by utilizing the cognitive abilities of the driver to augment the detection operation of the cruise control apparatus.