PURPOSE: To eliminate the restriction of a work place and to facilitate the adjustment and the conveyance by connecting a pulse detector to a controller, and outputting the speed of revolution of an engine of a vehicle to be measured by a pulse wave.

CONSTITUTION: One end of a wire 11 is detained to a turning shaft of a throttle valve 2, and the other end is detained to an output shaft of a pulse motor 6 so that an opening of the valve 2 can be adjusted by the motor 6. Subsequently, a pulse detector 8 for outputting the speed of revolution of an engine of a vehicle 1 to be measured by a pulse wave is connected to an input side of a controller 7, and a pulse output is provided to its motor 6. In such a way, by sending a pulse signal to the motor 6 from the controller 7 and rotating it by a prescribed opening, the valve 2 of the vehicle 1 to be measured can be set to an idle opening. Subsequently, in its state, a slow adjusting screw is rotated, and while detecting the pulse wave corresponding to the speed of revolution of the engine, the speed of revolution is set. Accordingly, an operating work of an accelerator and a throttle lever can be omitted, and also, a dynamometer is not used.