The sub-modi ‘competence’, ‘readiness’, ‘permission’, ‘ability’, ‘manageability’ including the modus of ‘possibility’, each having its marker and specific conditions of realization have been identified in the language of the diary by T. L. Sukhotina-Tolstaya. The study is made on the basis of lexical meaning of the modal modifiers, their functional context and pragmatics of utterance. The sub-modus ‘permission’ has the greatest lexical representation: its markers include the lexemes мочь , можно , возможно (be able, can, may). The sub-modus of ‘readiness’ is realized by lexemes готов (be ready) and в состоянии (be able). The ‘competence’, ‘ability’, and ‘manageability’ are represented by single modifiers, namely мочь , готов , уметь , успевать (be able, be ready, be competent, to manage) . At the bottom of the sub-modi objectification there are conditions which can be correlated either with the characteristics of the propositional qualities of the subject (the inner ones) or with the outer ones which do not depend on the subject. Functioning of the sub-modi ‘competence’, ‘readiness’, and ‘ability’ is defined by their inner conditions. The sub-modus ‘permission’ is realized both by means of inner and outer conditions. Some of them are relevant for the realization of a few sub-modi, others are compatible only with a single one. Considerable predominance of negative modifiers in the modus of ‘possibility’ and coincidence of the modal and propositional subjects are referred to specific features of «The Diary» as a special literary genre, and to one of the aspects of T. L. Sukhotina-Tolstaya’s idiostyle: the diary notes were being made during all her life, she used to write frankly «about herself and for herself».