An open-end wrench and a method of manufacturing the same are provided, the structure of which includes a body and a cover. The body includes a head portion and a handle portion, and the head portion includes a jaw portion and an opening formed at an inner side of the jaw portion. The cover includes a first plate, a second plate, and a third plate connecting the first plate and the second plate. An external surface of the third plate is formed to a wrench opening. A mouth is defined by external edges of the first plate, the second plate, and the third plate, and the mouth is penetrated by the jaw portion, so the cover wraps the jaw portion and the head portion is imbedded to the cover by using adhesive means.