A method for manufacturing a glass panel unit, the method comprising: an arrangement step of arranging a first substrate, including a glass pane, and a second substrate, including another glass pane, such that the first substrate and the second substrate face each other with a frame-shaped sealing material interposed between the first and second substrates, and thereby creating an internal space surrounded with the first substrate, the second substrate, and the sealing material; a bonding step of heating a glass composite, including the first substrate, the second substrate, and the sealing material, to melt the sealing material and thereby hermetically bond the first substrate and the second substrate together with the sealing material thus melted; an evacuating and hermetically sealing step of evacuating and hermetically sealing the internal space; a melting step; a curing step; and a seal opening step, the arrangement step including arranging a gas adsorption unit inside of the frame-shaped sealing material, the gas adsorption unit including: an activated getter; a package encapsulating the getter therein; and a low-melting member having a lower melting point than the package, the melting step including heating, and thereby melting, the low-melting member at a temperature lower than a melting point of the package to bond a connector, including the low-melting member, onto the package, the curing step including cooling and thereby curing, after the bonding step, the low-melting member that has melted in the melting step, the seal opening step including causing, either during, or after, the evacuating and hermetically sealing step, thermal stress resulting from a difference in thermal expansion coefficient between the package and the connector to the package connected to the connector and breaking the package open with the thermal stress to open a seal of the getter by the package. an arrangement step of arranging a first substrate, including a glass pane, and a second substrate, including another glass pane, such that the first substrate and the second substrate face each other with a frame-shaped sealing material interposed between the first and second substrates, and thereby creating an internal space surrounded with the first substrate, the second substrate, and the sealing material; a bonding step of heating a glass composite, including the first substrate, the second substrate, and the sealing material, to melt the sealing material and thereby hermetically bond the first substrate and the second substrate together with the sealing material thus melted; an evacuating and hermetically sealing step of evacuating and hermetically sealing the internal space; a melting step; a curing step; and a seal opening step, the arrangement step including arranging a gas adsorption unit inside of the frame-shaped sealing material, the gas adsorption unit including: an activated getter; a package encapsulating the getter therein; and a low-melting member having a lower melting point than the package, an activated getter; a package encapsulating the getter therein; and a low-melting member having a lower melting point than the package, the melting step including heating, and thereby melting, the low-melting member at a temperature lower than a melting point of the package to bond a connector, including the low-melting member, onto the package, the curing step including cooling and thereby curing, after the bonding step, the low-melting member that has melted in the melting step, the seal opening step including causing, either during, or after, the evacuating and hermetically sealing step, thermal stress resulting from a difference in thermal expansion coefficient between the package and the connector to the package connected to the connector and breaking the package open with the thermal stress to open a seal of the getter by the package.