The article reveals the concept of the professional potential of the teacher as the phenomenon that defines the essence of personally important results of the students’ training at the University. The author defines the role of updating the professional capacity in the process of changing the nature of pedagogical education. Two types of professional potential – realized and unrealized – are distinguished. The author defines certain functions and roles that are suitable and specific for professional teacher; different types of teacher’s activities are enumerated. The article highlights the results of experimental work that shows that the orientation of a would-be-teacher on updating his professional capacity enables most students to enter the productive and creative levels of readiness for professional activity, helps them to become active members of the professional community of educators.