[PROBLEMS] A method of sealing a glass panel assembly capable of properly removing impure gases or the like by a temperature control and a pressure control combined therewith in a sealing stage, and reducing the amounts of impure gases or the like remaining in the glass panel assembly after sealing; and a sealing furnace. [MEANS FOR SOLVING PROBLEMS] When sealing a glass panel assembly having a seal frit interposed between a pair of stacked glass substrates by fusing the seal frit, the interior atmosphere is forcibly fluidized to heat the glass panel assembly to a preliminary heating temperature T1 near the fusing start temperature of the seal frit by this interior atmosphere, then it is depressurized (P1) with the preliminary heating temperature kept unchanged, then the interior atmosphere is forcibly fluidized to heat the glass panel assembly from the preliminary heating temperature to a sealing temperature T2 by the interior atmosphere, and then the interior atmosphere is forcibly fluidized to cool the glass panel assembly by this interior atmosphere.