A tempered glass manufacturing apparatus includes a loading unit for loading sheets of glass therein. A heating unit receives the loading unit having sheets of glass loaded therein. The heating unit includes first to third openings. A tempering unit is connected to the heating unit through the first opening and receives the loading unit having sheets of glass loaded therein. The tempering unit performs a tempering process on the sheets of glass when the loading unit is positioned in the tempering unit. A residual salt discharging unit is connected to the heating unit through the second opening. An auxiliary layer providing unit is connected to the heating unit through the third opening of the heating unit. The auxiliary layer providing unit includes auxiliary layers for performing a residual salt preprocessing process to increase a removal of residual salt provided on surfaces of the sheets of glass.