To accurately and precisely mold a spherical glass gob having an arbitrary largeness regardless of the largeness of an outlet opening of a glass dropping nozzle by compulsorily dropping a molten glass from the glass dropping nozzle into a mold by the pressure of an inert gas.

Gas-jetting nozzles 6 are installed in three positions at 120° interval around a glass-dropping nozzle 3 arranged in the upper part of a mold member 2. When a molten glass flowing down from the glass-dropping nozzle 3 grows to a prescribed largeness at the outlet opening, nitrogen gas is jetted to the outlet opening from the obliquely upper direction, and the molten glass is compulsorily separated by the jetting pressure of the nitrogen gas at the step before the molten glass naturally drops, to drop the molten glass into the mold member 2 and to provide the objective spherical glass gob.