Analyzes motion of the cutter head of the AM-50 heading machine. Two types of head motion are comparatively evaluated: planar motion and spatial motion. The spatial motion consists of the head rotational motion and horizontal or vertical feed motion, while planar motion consists of rotational motion and vertical feed motion. Equations that describe head motion under conditions of cutter vertical or horizontal feed motion are derived. The angle between the cutting speed direction and working speed direction is defined. On the basis of these formulae variations of cutting speed depending on the cutting tool position on a cutter head are calculated. Calculations made for 2 extreme cutting tools show that the cutting speed ranges from 1,205 m/s to 3,512 m/s. 4 refs.