into the intake and exhaust chamber 12 in the arrow direction the end of the elevating rod 13 is supported in the inner cylinder 18 and sidably driven by a drive mechanism not shown a flexible sealing body 18 a is placed on the end of the cylinder 18 to hermetically seal with the getter room 3 when it is contacted against the getter room of the vacuum envelope 10 the cylinder chamber 13 b vertically moves the elevating rod 13 according to the present invention when the vacuum envelope 10 is conveyed into the sealing chamber 11 the opening is left around the periphery of the fritted glass 5 laminated on the vacuum envelope 10 hence as described later with reference to fig2 a high vacuum space can be obtained while the gas remaining inside the vacuum envelope 10 is being evacuated that is as shown in fig2 a the inner cylinder 18 is first lifted to be in strong contact with the vacuum envelope 10 conveyed inside the sealing chamber 11 in such a state the first valve 16 is opened to introduce gas at a high temperature into the vacuum envelope 10 as shown by the arrows since the fritted glass 5 to be formed as the side wall of the vacuum envelope 10 is not completely sealed the gas charged into the envelope 10 flows through the space between the first substrate 11 and the second substrate 12 in the arrow direction the gas flows through the space in the vacuum envelope 10 and then is discharged out through the fritted glass portion 5 not sealed the flow of the high temperature gas allows the gas contents mainly moisture remaining inside the envelope 10 to be exhausted sufficiently the.