To provide a method for producing a reinforced glass substrate capable of producing two types of reinforced glass from the same material, one of which has high mechanical strength and the other of which has high cutting properties.

The method for producing the reinforced glass substrate comprises: preparing a glass raw material that is blended so as to have a glass composition containing 40-71% SiO₂, 3-23% Al₂O₃, 0-3.5% Li₂O, 7-20% Na₂O and 0-15% K₂O, by mass%; melting the glass raw material; forming the glass raw material into a plate shape; then controlling a concentration of Na ion in KNO₃ molten salt; and then subjecting the obtained glass substrate to an ion exchange treatment in the KNO₃ molten salt to form a compressive stress layer on a surface of the glass.