The article refers to the problem of inadequacy of the classification of the constitution due to the mode amend them. The purpose of the analysis was to determine the scope of the diversity of procedures for the amendment of constitutions as well as to create a typology of such procedures, with consideration to their individual components, their functions and effects of their use. To this end, I conducted a review of applicable solutions in terms of grouping related institutions. Considerations begin with indication of systemic importance of amendment procedures, the reasons for the use of stringent solutions and low popularity of flexible acts. For this purpose, it was necessary to present the origin and foundations of the division into rigid and flexible constitutions. Two-step classification proposed by JB Bryce over 130 years ago is not applicable to modern constitutions. The new three-step classification takes into account hedging instruments, which are used in the constitutions created in the twentieth century. The analysis included the following stages of work on the revision modern European constitution. As a result, they managed to identify different types of instruments intended to ensure the functionality and stability of the political system. Because of its universal nature it can be applied to all of the constitution historical and current, regardless of the provisions made for their protection.

The Finnish Basic Law is rigid and may be amended only by a special procedure. Following the Nordic tradition, this matter has been treated as a peculiar case of changing ordinary laws. It consists in deferral of the bill in the second reading until the first parliamentary session of the next term of office after the elections. The aim of the study is to determine the degree of adaptation of the Basic Law of Finland to the systemic reality in connection with the state’s participation in the processes of the European integration.