The issue raised in the article is related to the reasons behind serious attitude toward political significance of musical art in Ancient Greece. It is claimed that almost universal acceptance of the concept of direct impact of music on customs and moods of listeners was the cause of such attitude. Ancient Greek practice assumed possibility of legislative establishment of a duty of citizens to be trained in playing musical instruments. Besides, there was a widespread phenomenon - technical and acoustical standards were perceived as the precepts of law, with the obligatory sanctions for their non-compliance. Existence of the special sanctions which are closely connected with music is curious: the obligation to compose and sing a dishonoring song about a guilty man, a ban imposed on noble songs singing, and so on. Certain civil duties, like a horegiya, were as well related to music. It is claimed in article that originally such a duty was assigned not simply to rich citizens, but to those ones who understood the basis principles of musical art. As well, privileges provided by the government to the winners of musical competitions, are of interest for the author.