Method of manufacturing glass melt and method of manufacturing molded glass material

A method of manufacturing a glass melt containing fluorine comprising:

• melting glass raw materials including materials containing fluorine;
• and
• refining the resulting glass melt, wherein:
• the refining is conducted in a refining vat equipped with a flow inlet through which flows glass melt obtained by heating and melting the glass raw materials, and a flow outlet through which flows glass melt that has been refined, and comprises:
• maintaining the level of the glass melt in such a manner that the flow inlet and flow outlet remain beneath the surface of the glass melt and the glass melt does not contact external air, and
• maintaining the level of the glass melt in the refining vat by monitoring the level of the glass melt in a surface monitoring vat having an opening in the upper portion thereof and connected to the refining vat in such a manner that the level of the glass melt in the surface monitoring vat is identical to the level of the glass melt in the refining vat;
• wherein a gas is discharged from an interior of the refining vat in such a manner that the pressure within the refining vat is kept about the same as atmospheric pressure.