Abstract: An inductive transformer-type storage device comprising a primary winding and a secondary winding arranged inside the primary winding coaxially thereof. The secondary winding has a substantially greater number of turns than the primary winding and is enclosed in a hermetically sealed casing filled with dielectric having an electric strength of at least 50 kV/cm. The hermetically sealed casing also encloses the gap between the windings, which gap is selected so as to ensure the break-down strength in the dielectric, as well as an interwinding coupling factor of 0.2 to 0.8. The inductive storage device is intended for supplying power to installations generating powerful relativistic electron beams.