A bistable magnetic holding device, which includes: a nonmagnetic support casing in the form of a channel with a rectangular cross-section; a magnetic core including a base and three legs set perpendicularly to the base, the two outer legs and the base forming a “U”; a permanent magnet in the form of a bar inserted between the base and the middle leg; a coil surrounding the middle leg; a flat movable part; and a return motion and guidance means built into the inside walls of the support so as to allow return motion, toward the upper part of the support casing, of the magnetic core.