Abstract: A cutting head for a cord type mower which severs grass and weeds with cords unwound from a cord spool provided within a bowl-shaped rotary casing and radially projected from the rotary casing by rotating the rotary casing at a high rotating speed. A speed change control mechanism is provided within the rotary casing to control the rotating speed of the rotary casing so as to vary it according to the length of the projecting portions of the cords. When the cords wear and shorten, the moment of inertia of the cutting head decreases; consequently the rotating speed of the rotary casing increases and thereby the cords are fed out automatically by the increased centrifugal force acting on the cords. Then, the engaging members members engaging the speed change control plate are moved radially outward by the centrifugal force to reduce the rotating speed of the rotary casing. Thus, the cords are always projected by a predetermined length from the rotary casing for stable mowing operation.