Introduction. Increasing the effectiveness of the activity of the internal affairs bodies of the Russian Federation in modern conditions focuses on psychological factors of its implementation both individually (by particular employees) and in the process of cooperative actions (by service staffs). Special consideration should be given to the role of the head as an organiser and regulator of the activities of subordinate employees, who is responsible for the quality and legality of their actions. Existing ideas on the interaction of service staff members characterise the role of the head in different ways, but empirically insufficiently verify its significance in teams with different levels of functional relations and normative behaviour. The prerequisite of the present research is the replenishment of scientific and practical knowledge of the role of the head of the service staff as a regulator of functional relations and normative behaviour of internal affairs officers. The purpose of the research is to reveal the significance of the attitude to the head of the service staff when assessing the influence of functional characteristics of relations in the service staff on the understanding normative behaviour among its members. Research methods. A set of psychodiagnostic questionnaires was used: ‘Subjective assessment of intragroup relations’ (S. V. Dukhnovsky, K. V. Zlokazov), ‘Attitude of an employee to the performed activity, his direct supervisor and his reputation’ (A. A. Sarsenova), ‘Normativity. Intelligence. Regulation’ (S. V. Dukhnovsky, V. M. Kofanov). The sample of the research consisted of 160 employees of internal affairs bodies (112 males and 48 females aged from 29 to 43 years). Regression analysis was used as a method of data processing. Results. The authors found out that the normative behaviour of service team members is determined by functional-negative characteristics of their interaction and is an independent cause of service discipline violations. This fact testifies that negative forms of interaction of service team members (aimlessness, uncontrollability, connivance) as well as relations (hostility, negativism and conflict) reduce the level of normative service behaviour. It is determined that the attitude of employees to the head of the service team mediates the influence of functional-negative characteristics, acting as a regulator of their service behaviour. The results of the research expand scientific ideas on psychology of management of formal groups (by the example of service staffs) and can be used in preparation of employees of internal affairs bodies for positions of junior and middle supervising staffs.