Аннотация:Results of a spectroscopic and photometric investigation of the central region of M31 are presented. An analysis of absorption-index radial profiles involving magnesium, calcium, and iron lines has shown that an unresolved nucleus of M31 is distinct by its increased metallicity; unexpectedly, among two nuclei of M31, it is the faintest one locating exactly in the dynamical center of the galaxy (and dynamically decoupled) which is proved to be chemically distinct. The Balmer absorption line H beta has been included into the analysis to disentangle metallicity and age effects; as a result, an age difference of 3 times is detected between stellar populations of the nucleus and of the bulge, the nucleus being younger. A morphological analysis of CCD images has revealed a presence of nuclear stellar-gaseous disk with a radius of some 100 pc, the gas component of which looks non-stationary, well inside the bulge of M31.