Abstract: A chain saw guide bar having a lubricant feeding structure is capable of providing sufficient lubrication to the guide bar tip portion and has sufficient strength and durability during use over an extended period of time and, at the same time, has the weight of the guide bar reduced. The chain saw guide bar is made of a single plate and is provided with a lubricant supply port made in a base end portion of the guide bar surface, a bottomed recess groove running continuously from the lubricant supply port to a tip portion and bottomed holes located on the bottomed recess groove. The side walls of the holes and the recess groove are tilted to increase the widths of the cross sections of the recess groove and the hole toward the bottom.