A method for manufacturing a glass panel unit, the method comprising: an assembling step; a setting step; a determining step; and an installation step, the assembling step being a step of preparing an assembly, the assembly including a first glass pane, a second glass pane facing the first glass pane, a peripheral wall located between the first glass pane and the second glass pane and having a frame shape, an inside space surrounded by the first glass pane, the second glass pane, and the peripheral wall, a partition dividing the inside space into a first space and a second space, an evacuation port connecting the second space to an outside space, and an air passage configured such that the first space is evacuated through the evacuation port, the air passage having a slit, the slit being in contact with an inner peripheral edge of the peripheral wall and being disposed between the peripheral wall and the partition, the setting step being a step of setting a plurality of holder installation areas along an outer peripheral edge of the peripheral wall, the determining step being a step of determining that each of the plurality of holder installation areas is a first area or a second area, the slit and the peripheral wall not being adjacent to each other in the first area, the slit and the peripheral wall being adjacent to each other in the second area, the installation step being a step of providing a holder in the first area without providing the holder in the second area. an assembling step; a setting step; a determining step; and an installation step, the assembling step being a step of preparing an assembly, the assembly including a first glass pane, a second glass pane facing the first glass pane, a peripheral wall located between the first glass pane and the second glass pane and having a frame shape, an inside space surrounded by the first glass pane, the second glass pane, and the peripheral wall, a partition dividing the inside space into a first space and a second space, an evacuation port connecting the second space to an outside space, and an air passage configured such that the first space is evacuated through the evacuation port, the air passage having a slit, a first glass pane, a second glass pane facing the first glass pane, a peripheral wall located between the first glass pane and the second glass pane and having a frame shape, an inside space surrounded by the first glass pane, the second glass pane, and the peripheral wall, a partition dividing the inside space into a first space and a second space, an evacuation port connecting the second space to an outside space, and an air passage configured such that the first space is evacuated through the evacuation port, the air passage having a slit, the slit being in contact with an inner peripheral edge of the peripheral wall and being disposed between the peripheral wall and the partition, the setting step being a step of setting a plurality of holder installation areas along an outer peripheral edge of the peripheral wall, the determining step being a step of determining that each of the plurality of holder installation areas is a first area or a second area, the slit and the peripheral wall not being adjacent to each other in the first area, the slit and the peripheral wall being adjacent to each other in the second area, the installation step being a step of providing a holder in the first area without providing the holder in the second area.