A cutting head for use with a cutting tool, such as a grass trimmer. The cutting head has a housing, a line spool and a supporting cap. One end of the housing is coupled to an end of a motor output shaft and another end has an opening. A line spool is disposed in the housing and rotates along with the housing. At least one end of a line wound around the line spool extends out of the housing. The supporting cap is rotatably disposed at the end of the line spool adjacent to the opening and is exposed to an exterior of the housing through the opening.