This paper proposes an automotive cruise control system, using a self-tuning type controller and a stepping motor type actuator. The dynamic characteristics of vehicles change widely according to differences in the vehicle itself, such as engine type or vehicle weight, differences in vehicle speed range, and external disturbances such as changes in road incline or air resistance. The time delay control (TDC) method was introduced as an effective control method for systems with dynamic characteristics like this. Qualitative rules were also constructed to estimate driving conditions using vehicle speed error and the control input to the actuator, which opens and closes the throttle valve. A Self-tuning algorithm was developed, which automatically adjusts the control gain and the acceleration at the resuming operation using these rules. Cruise control experiments were performed for several different vehicles using this algorithm and good results were obtained.