Glass panel unit manufacturing method and glass window manufacturing method

A glass panel unit manufacturing method, comprising:

• an adhesive disposing step of disposing a glass adhesive on a first substrate, the glass adhesive including glass powder and a binder and having a shape of a frame having one part formed as a low step part to form a degassing gap, the first substrate including at least a first glass substrate, the low step part having a thickness smaller than a thickness of a remaining part of the frame;
• an opposite disposition step of disposing a second substrate including at least a second glass substrate to face the first substrate and forming the degassing gap at the part where the low step part is provided;
• an inner space forming step of heating a glass composite including the first substrate, the second substrate, and the glass adhesive to remove the binder and to melt the glass adhesive to form an inner space surrounded by a melted substance of the glass adhesive between the first substrate and the second substrate;
• a pressure reducing step of removing gas in the inner space to reduce a pressure of the inner space;
• and
• a vacuum space forming step of hermetically enclosing the inner space while keeping inner space in a pressure-reduced state to form a vacuum space which is hermetically separated from the inner space.