A method for producing molten glass, which comprises melting granules of a glass raw material mixture in a gas phase atmosphere so that at least a part of the granule particles is melted to form molten glass particles and collecting the molten glass particles to form molten glass, wherein the granules contain silica sand as a glass raw material, characterized in that the method comprises producing the granules by mixing glass raw materials, followed by granulating the mixture by a tumbling granulation method without pulverizing it, and the granules satisfy the following conditions: in a particle size distribution curve obtained by sieving the granules by means of a sieve having 1 mm openings and measuring the granules passed through the sieve by a dry laser diffraction scattering method, D50 representing the cumulative volume median diameter is from 466 to 800 μm, the average particle size of the silica sand in the granules is from 20.7 to 40 μm, provided that the particle size distribution curve of silica sand to be used as a glass raw material is measured by a wet laser diffraction scattering method, and D50 representing the cumulative volume median diameter in the obtained particle size distribution curve is taken as the average particle size of the silica sand, and in a particle size distribution curve obtained by measuring water-insoluble particles which are water-insoluble components of which the amount soluble in 100 mL of water at 20°C is less than 1.0 g and which are particles to constitute the granules by a wet laser diffraction scattering method, the ratio of D90/D10 is at least 10, where D10 represents the particle size of the 10% cumulative volume from the small particle size side and D90 represents the particle size of the 90% cumulative volume from the small particle size side, wherein the granules have a bulk density of at least 64% as measured by a mercury intrusion technique with bulk density [%] = 100 - porosity [%], and the granules have a crushing strength of at least 1 MPa with a value of the crushing strength of the granules being an average value of values (unit: MPa) obtained by measuring the crushing strength by the method in accordance with JIS R1639-5 with respect to from 50 to 100 granule particles optionally sampled from the granules. in a particle size distribution curve obtained by sieving the granules by means of a sieve having 1 mm openings and measuring the granules passed through the sieve by a dry laser diffraction scattering method, D50 representing the cumulative volume median diameter is from 466 to 800 μm, the average particle size of the silica sand in the granules is from 20.7 to 40 μm, provided that the particle size distribution curve of silica sand to be used as a glass raw material is measured by a wet laser diffraction scattering method, and D50 representing the cumulative volume median diameter in the obtained particle size distribution curve is taken as the average particle size of the silica sand, and in a particle size distribution curve obtained by measuring water-insoluble particles which are water-insoluble components of which the amount soluble in 100 mL of water at 20°C is less than 1.0 g and which are particles to constitute the granules by a wet laser diffraction scattering method, the ratio of D90/D10 is at least 10, where D10 represents the particle size of the 10% cumulative volume from the small particle size side and D90 represents the particle size of the 90% cumulative volume from the small particle size side,