The utility model provides a cable length -measuring appliance for measure the cable of certain length. Rear side at the base is equipped with the wire winding assembly, the wire winding assembly includes first pivot, reel and pivot supporting seat, be equipped with in first pivot with the reel of first pivot synchronization action, be equipped with the rotatory actuating mechanism of the first pivot of drive on the base, be equipped with the response piece in the side of reel, be equipped with and respond to the counter of a mating reaction on the base, the counter has constituted the measurement assembly with the response piece, be equipped with the unwrapping wire assembly in the front side of base, the unwrapping wire assembly includes second pivot, drum and pivot supporting seat, the drum setting in the second pivot and with second pivot synchronization action, be equipped with tight line assembly between the assembly in unwrapping wire assembly and wire winding, tight line assembly includes crossbeam, stationary magazine creel, telescopic link, spring and gyro wheel, and the winding was on the reel after cable on the drum passed the gyro wheel. The device can realize the precision measurement to the cable length.