PURPOSE: To obtain high quality discharged glass without causing devitrification or forming striae by connecting plural pipes to the lower part of a glass melting vessel and properly changing over the pipes without exchanging to obtain a desired flow rate of glass.

CONSTITUTION: Plural prescribed pipes 4, 6 for discharging glass are connected to the lower part of the side wall of a glass melting vessel 2. Molten glass 10 is discharged from the pipe 6 and simultaneously a small amt. of molten glass is discharged from the pipe 4.