A grass trimmer includes a cutting head for mounting a cutting member, a drive head having a output shaft for driving the cutting head to rotate, and an anti-winding member for preventing the output shaft from being wound to by grass. The drive head includes a drive device to drive the output shaft and a head housing for accommodating the drive device. The output shaft connects to the cutting head and passes through the anti-winding member and the anti-winding member is mounted to the cutting head so as to rotate with the cutting head and is disposed between the cutting head and the head housing so as to fill the space between the cutting head and the head housing.
