The present invention relates to a float glass for chemical strengthening, containing a bottom surface coming into contact with a molten metal at the time of forming and a top surface opposing the bottom surface, in which a difference (NNa.sub.2O.sup.2) determined by subtracting a square of a normalized Na.sub.2O surface concentration of the bottom surface which is a value obtained by dividing an Na.sub.2O concentration in the bottom surface by an Na.sub.2O concentration at a depth position of 100 m therefrom, from a square of a normalized Na.sub.2O surface concentration of the top surface which is a value obtained by dividing an Na.sub.2O concentration in the top surface by an Na.sub.2O concentration at a depth position of 100 m therefrom, is 0.040 or less.

To provide a method for forming molten glass, capable of easily improving the forming accuracy of molten glass. One embodiment of the method for forming molten glass of the present invention comprises a supplying in which molten glass having a temperature of at least the softening point is discharged in a strip shape and supplied on the surface of molten metal, and a transporting the glass ribbon supplied on the surface of the molten metal, wherein the transporting includes a cooling the glass ribbon being transported, in a region on the upstream side in the transport direction, so that the temperature of the glass ribbon becomes lower than the softening point in the entire width direction.

To provide a method for forming molten glass, capable of easily improving the forming accuracy of molten glass. One embodiment of the method for forming molten glass of the present invention comprises a supplying in which molten glass having a temperature of at least the softening point is discharged in a strip shape and supplied on the surface of molten metal, and a transporting the glass ribbon supplied on the surface of the molten metal, wherein the transporting includes a cooling the glass ribbon being transported, in a region on the upstream side in the transport direction, so that the temperature of the glass ribbon becomes lower than the softening point in the entire width direction.