Considering, in the current situation, the importance of principles and their influence on all branches of law, especially in constitutional and procedural law, the constitutional criminal principles were investigated, more specifically the principle of individualization of the penalty, which enshrines the material equality in all its stages: legislative, judicial and enforcement. In order to present a constitutional hermeneutic of the principle of individualization in the face of the three-phase criterion of dosimetry used by the judge, it is salutary that the magistrate, judge par excellence, analyzes the personality of the agent, which should be understood as a synthesis of moral and social qualities, as well as his greater or lesser ethical and social sensitivity. Therefore, when proceeding to individualization, the magistrate must assess in a unique way the conduct of each agent, going through all the circumstances of subjective and objective nature, in analysis of the three-phase system of dosimetry of the penalty, to only then erupt the will to judge. Now, man was not born to live alone. From here we must extract the legal brocardo "non est enim singulare nec solivagum genus hoc".