PURPOSE: To reproduce the actual traveling performance of a tested vehicle and obtain a high-reliability test result and to automate various tests by placing all wheels on the vehicle to be tested on traveling belts and supporting the rear or front part of the vehicle freely.

CONSTITUTION: A belt traveling device 3 is equipped with traveling belts 10 which run while all wheels 14 and 15 of the vehicle 13 to be tested are mounted. A vehicle support device 4 is installed nearby at least one end of the device 3, bears the rear end of the vehicle 13, and makes a couple of vehicle clampers 52 for holding the rear end follow up the behavior of the vehicle 13. Consequently, a traveling test is conducted while the vehicle 13 is placed in the same environment with actual traveling environment through the belts 10 corresponding to a road surface state, so the test result matching with the actual traveling state is obtained as compared with a test conducted while the wheels are mounted on a rotary drum, and the actual vehicle traveling performance is reproduced. Further, the true behavior state is maintained 52 in traveling environment without restricting or changing the behavior of the vehicle 13, so the high-reliability test result is obtained in the same environment with actual vehicle traveling.