The article considers the methodology" Action Research " (Research in action) as an effective tool for introspection and professional development of teachers. The possibilities of" Action Research " are analyzed in the context of the study of one's own experience, its advantages over traditional methods of reflection differ. The article presents the structure and stages of" Action Research", and also describes examples of using the method in educational practice. The conclusion summarizes the high value of "Action Research" for the continuous professional growth of teachers. In the context of the study and analysis of the teacher's own experience, the effectiveness of the "Action Research" method is considered. "Action Research"is a cyclical process that allows teachers to systematically study their experiences, identify problems, and develop strategies to solve them. This approach focuses on how it contributes to the professional development of teachers, improving the quality of education and increasing the motivation of students. Examples of the successful use of "Action Research" in various educational institutions and the areas of its application in practical pedagogy are given. The article identifies the effectiveness and weaknesses of the use of the research approach in action during the lesson, studies are carried out on the extent to which the methods and evaluation strategies used during the lesson achieve results.