Self-reflection is viewed as a mental activity in which preschool teachers (educational professionals) have a chance and tendency to develop a level of self-reflection on their own practice, its purpose, obtained results, and development. In the first part of the paper, the author looks at epistemological tenets of other approaches (positivist, anti-positivist, constructivist, post-modernist, and transformational) on which the self-reflection approach is based, and then interprets and analyzes the specificities of the self-reflection approach. The aim of the paper is to elaborate on self-reflection as an epistemological approach using a case study as an example, in order to clarify and understand better the theoretical assumptions underlying this approach. The case study was used as a paradigmatic case in which self-reflection is emphasized as the epistemological approach to the research of pedagogical issues, and an effort has been made to use it for making a valid example. The concluding part of the paper contains conclusions obtained via theoretical analysis and the case study, including the formulation of the aspects of pedagogical actions that could be improved by using this approach - initial theoretical and practical education of educator, professional training and research, as well as the competences of teachers who educate pre-service educator.