PURPOSE: To test a steering-linked control function which works to control rotation of at least one wheel in response to the steering operation of an automobile, while driving the automobile on a testing device.

CONSTITUTION: An automobile is driven with each of the wheels of the automobile put on a roller 11, 22 with which a testing device is equipped. While the automobile is running, a pseudo-steering signal is input to an onboard controller via a coupler 11 and a steering controlling state is thereby simulated so as to cause a steering-linked control function to work. Signals from a means 9 for detecting the rotary fluctuation of the roller 11, 22 are input to a monitoring device 10 and control functions are tested according to the relationship between the rotary fluctuation of a wheel whose control function is to be controlled and that of a non-controlled wheel.