Abstract: A head for a line trimming apparatus includes a body member and a detachable cover which may include a replaceable insert for connecting the head to a drive shaft of a line trimming apparatus. The body member includes opposed openings and a filament receiving channel for inserting an elongated flexible cutting filament into the head for retention thereon. A spring biased clamp is supported on the body member and is engageable with the filament portion residing in the channel to releasably retain the filament connected to the head. An actuator button projects through an opening in the body member and is operable to be pressed to cause the clamp to release forcible engagement with a filament so that the filament may be removed and replaced. In one embodiment the clamp and actuator are an integrally formed part and the filament projects through openings formed in spaced apart arms of the clamp member.