A vegetation cutter includes a tubular casing and a power source is connected to a first end of the casing so as to drive a drive cable which extends through the casing. A cutting member is connected to the drive cable and located on a second end of the casing. A positioning tube is axially located in the casing and has an annular sleeve through which the drive cable extends. The sleeve has two rib portions tangentially connected thereto and the two rib portions are parallel to each other. Each rib portion has two ribs on two ends thereof and the two ribs contact an inner periphery of the casing. The ribs are flexible and position the positioning tube in the casing, and absorb vibration when in use.
