PURPOSE: To eliminate unnecessary deceleration and acceleration after the deceleration to improve the comfortability of drive and the economy of fuel consumption, by providing a means for controlling acceleration and deceleration to maintain a vehicle speed before variation in the distance between vehicles.

CONSTITUTION: A vehicle-to-vehicle distance detecting device 1, a sensor 17 constituting a vehicle speed detecting means 13, a set switch 19 instructing constant travel travel, etc. constitute a vehicle travel control device, and processing is made by a microcomputer 23 in accordance with the output signal of a throttle valve opening degree control means under the sequence of the flow chart to change the opening degree of a throttle valve by means of a throttle valve opening degree control means 13. A microcomputer 23 has a CPU25, a ROM27, a RAM29 and an input/output port 31. The distance between vehicles with respect to the preceding vehicle is detected to maintain a safety distance between vehicles, and if the speed of the preceding vehicle is higher than the speed of the instant vehicle, exceeding a predetermined amount, the vehicle speed is maintained with no speed control being carried out.