A security device for improving the security against falsification of articles has a carrier element (10). Arranged on the upper side of the carrier element (10) are a large number of diffractive surface elements (18). The surface elements (18) respectively form a number of surface element groups, surface structures of which are made to match one another in such a way that they show a point (28) of the symbol to be represented over an entire observation sphere. By changing the angle of incidence of the light and/or the angle of observation of an observer, a continuous movement of the symbol in the observation sphere is perceived by the observer.