To provide a traveling state simulating apparatus capable of accurately reflecting road conditions assumed in advance and simulating the travel of vehicles in vehicle performance tests.

In the test system having no mounted brake system, which is mounted to an actual vehicle, for simulating the traveling state of vehicles by absorbing drive output of an engine 10 and a motor generator 20 by load absorption motors 50a and 50b directly connected to a drive shaft 40, a travel simulation device 60 changes a value of gradient resistance Rg indicated in driving conditions according to the distance D traveled by a vehicle and makes the load absorption motors 50a and 50b generate load torque computed on the basis of the changed driving conditions.