To provide a manufacturing method which, when a space between a pair of glass substrates is airtightly sealed by local heating using electromagnetic waves, improves adhesiveness and reliability of a sealing layer to both glass substrates.

First and second sealing material layers 5, 6 each formed of a calcined layer of a sealing glass material having electromagnetic wave absorptivity are formed in sealing areas of first and second glass substrates 1, 2. The first glass substrates 1 and the second glass substrate 2 are laminated to each other while bringing the first sealing material layer 5 and the second sealing material layer 6 into contact with each other. The first and second sealing material layers 5, 6 are locally heated by irradiation of electromagnetic waves thereto to melt and solidify the first and second sealing material layers 5, 6, whereby a sealing layer 8 is formed which airtightly seals a space between the first glass substrate 1 and the second glass substrate 2.