The paper presents the argumentation for the requirement of the canonical form of marriage, which has been required ad validatem matrimonii since the Trident Council. In the face of the critics and postulates of abolishing the necessity of mandatory character of the form in question, the author presents its stricte ecclesiastical significance. In the face of secularisation, the canonical form of marriage is to be not only help for the Church to exercise effectively its jurisdiction over marriages, but also and foremost, be a mean of testimony about the sacramentality of marriage. The form can be also a guarantee of authentic nuptial signification for the people who are entering marriage and also ad extra to the world.