PURPOSE: To make fixed speed running unavailable to start when acceleration/ deceleration operation is ended, and to set a lower limit value to an upper limit value of a low speed region so as to avoid unconformity in the fixed speed running in the low speed region, by eliminating fixed speed running indicating information when a moving speed of a vehicle is a lower limit value or less.

CONSTITUTION: A moving speed of a vehicle is accelerated/decelerated by a throttle valve 11 and a motor 50, also to detect similarly the moving speed by a reed switch LSW and a rotary permanent magnet Mag. Decelerating operation by a driver is detected by a position sensor shift lever 165, brake switch BSW1 and a deceleration indicating switch DSW, also to set fixed speed running indicating information by an MPU 101. Further in the MPU 101, when the moving speed is a lower limit value or less, and when the moving speed is not more than the second limit value lower than a target speed to provide deceleration operation before, the fixed speed running indicating information is eliminated. During the time with the fixed speed running indicating information provided, the moving speed is accelerated, when it is lower than the target speed, further decelerated when higher than the target speed.