PURPOSE: To easily make a reactor adaptable to various rated currents such that the impedance is reduced during the feeding of the rated current and increased at the time of occurrence of an excessive current, by a construction wherein a plunger is supported by a return spring, and the plunger is driven to be attracted into a coil by the magnetic force of the coil when the excessive current occurs.

CONSTITUTION: A current limiting reactor is connected in series to wiring lines (not shown) through a terminal unit 19, and a coil 8 serves as an electric line element. The illustrated state represents the normal state where the rated current is fed. At this time, since the resilient force of a return coil spring 25 is stronger than the plunger attracting force (magnetic force) caused on the coil 8, the plunger 22 is held in a chamber 24. Thus, the current limiting reactor has an impedance value based on the hollow coil. This make it possible to set the impedance relatively small for feeding of the rated current.