This creation is intended to provide a kind of grass trimmer handpiece structure, it is mainly that the bottom of what crosshead body is equipped with the first pivoting portion in conjunction with mowing cutter, and the side of the head body is equipped with for connecing the second pivoting portion for setting long rod, and its characteristic is in what: the port system of first pivoting portion extends inwardly at least one slot, hot-air to guide head inside the main body is discharged, in order to reaching the effect of inside and outside air of the head body is connected and reaches ventilation, heat dissipation person.本創作旨在提供一種割草機機頭結構，主要係於機頭主體之底部設有結合割草刀具之第一樞接部，且該機頭本體之一側設有供接設長桿體之第二樞接部，而其特徵在於：第一樞接部之端口係向內延伸出至少一條槽，用以導引機頭主體內部之熱空氣排出，俾達到使該機頭本體內、外空氣導通而達到換氣、散熱之功效者。
