The invention relates to a security device for improving the security against the falsification of articles, having a support element (10). A plurality of diffractive surface elements (18) are arranged on the surface of the support element (10). Each surface element (18) forms multiple surface element groups, the surface structures of which match one another so as to make precisely one point (28) of the corresponding symbol to be displayed visible to an observer under specified viewing conditions. By changing the angle of incidence of the light and/or the angle of observation of the observer, a continuous movement of the at least one symbol is perceived by the observer.