Rotary Drum Mowers are connected to tractor via three-point hanging system and get its drive from the PTO at 540 rpm and transmit to the drums through belt pulley. It is a grass mowing machine with free oscillated blades which are on the two drums rotating in reverse to each other with this system to cut green feed plants (clover, grass plants, barley, oat, etc.) being opened by the effect of centrifugal force and leave on the surface of the field in barrel state. Drum Mowers which are manufactured ideal for all sorts ofthe farms are designed to use with the tractors having lower and medium horse powers. Rotary Drum Mower is protected against the damages which may incur due to some roughness on the field. The belts are tightened by means of a spring and thus the safety is ensured on the pulley mechanism.Its adaptation to the unevenness of the ground is highly successful.