PURPOSE: To provide an inter-car distance control device which can automatically set the target inter-car distance in compliance with the degree of fatigue of the driver, and to provide an inter-car distance alarming device which can set the alarm issue distance automatically.

CONSTITUTION: An inter-car distance control device comprises an inter-car distance measuring means 1 to determine the actually measured distance between the car concerned and the foregoing car, a car speed measuring means 2 to measure the car speed of the car concerned, a running time measuring means 3 to measure the running time since the car began running, the first target distance calculating means 4 to calculate the first target distance, the second target distance calculating means 5 to calculate the second target distance, and a throttle opening/closing control means 6 which compares the actually measured inter-car distance with the second target distance and controls opening and closing of the throttle of the car concerned on the basis of the result from comparison.