To provide a device allowing some control or some operation according to vehicle speed and having a wide applicability.

A revolution from a speedometer gear 5 already provided at a transmission 3 of a vehicle diverges at a diverging unit 7, one being transmitted to a speedometer 10 serving as an original output while the other being input to a rotary encoder 11 at which output pulses are obtained. The rotary encoder 11 is capable of generating extremely many pulses per one revolution, so that every time the vehicle moves ahead a given little distance, one pulse can be obtained. Since the existing speedometer gear 5 is utilized, low cost can be achieved.