The present study examines the professional development problems of a high school teacher. High school teacher is both a scientist and a teacher. Teaching and research activities are integrated by his methodical activity. Methodical competency of a teacher is defined as a basis in the context of Competence-based Education. Methodical competency building model is founded upon recursion. Recursion, as a technique based on consistent reduction of a complex problem solution to solutions to a set of "simpler problems" of the same class and obtaining on this basis the solution to the original problem, allows the teacher to build an individual route to form and develop methodical competency. Teacher performs different types of methodical activities (educational and methodical, scientific and methodical, organizational and methodical, and examination and methodical activities) in "non-linear" way, as well as assimilates the corresponding methodical roles (engineer, researcher, expert, manager, and teachers' coach). Actually, the beginning of assimilation of one role is accomplishment and/or continuation of the other role. Thus, the methodical competency structures, recursively referencing to each other, are developed out of themselves.