[Object] Object of the present invention is to improve accuracy of the travelling test of a tested vehicle on a chassis dynamometer, and to increase realistic feeling of the travelling test.[Means to solve] A driver's aid device 5 displays, on a main screen 11, a travelling speed pattern 12 that is a driving pattern for performing a performance evaluation test of a tested vehicle 6. The main screen 11 displays thereon topographical feature information 13 of a road where the travelling test is carried out. A marker 14 that indicates a vehicle state is shown at an intersection of the topographical feature information 13 and a reference line 15 that indicates a present position of the tested vehicle 6. This marker 14 is shown with the marker 14 inclined in accordance with a gradient of the road where the test is carried out. Further, a curve band 28 indicating curve information of the road where the travelling test is carried out is shown on the main screen 11. The curve band 28 is shown with a color of the curve band 28 changed in accordance with an angle of the curve. In addition, the travelling speed pattern 12 is created on the basis of data of GPS or a map data 10. Furthermore, a travelling route where the travelling test is carried out is displayed on an auxiliary display device on the basis of data to create the travelling speed pattern.