An activating magnet having two coaxial pole tube portions which are spaced from each other, have the same inner and outer diameters and are connected with each other by means of a connecting ring of solder. In order to create an activating magnet in which the pole tube portions need only be machined on the outside or inside diameter, a spacing ring of a non-magnetizable material is arranged between the two pole tube portions. The spacing ring is thinner than the two pole tube portions, whereby the connecting ring has the same outside diameter and the spacing ring has the same inside diameter as the pole tube portions, or vice versa. A guide tube of a non-magnetizable material may be provided within the pole tube portions and the spacing ring.