PURPOSE: To provide a means capable of ceasing an emergency running means.

CONSTITUTION: A measuring device 10 is provided for measuring a position of a member, such as a throttling valve, a control rod or an accelerator pedal, which adjusts an output of a vehicle. The measuring device comprises a switching means 32 functioning as at least a first sensor 12 and a second sensor and generates a signal value showing the position of the member. Further, in order to detect malfunction of the sensors, a logic circuit 40 is provided to evaluate output values of these two sensors. Subsequent to the malfunction detection of either of the sensors, the function of the sensor is identified to be normal if the output signal of the sensor exceeds an upper threshold and a lower threshold.