AbstractFor multi‐dimensional cosmological models we investigate the dynamics of both, scales and dimensions. The classical equation of motions and the corresponding Wheeler‐de Witt equation are set up generally and the qualitative behaviour of the system is discussed for some specific model with 2 factor spaces: A spaceM1with dynamical dimension, and a compact internal spaceM2of constant dimension. With a natural choice of some contraint, there exist a solution whereM1expands as usual space whileM2is shrinking down to unobservable sca