A glass panel unit manufacturing method includes a punching step and a pillar mounting step. In the punching step, a punch punches at least one of a plurality of portions from a base material of a sheet to form at least one pillar. Each of the plurality of portions is surrounded by a corresponding one of a plurality of loop-shaped grooves in the base material. In the pillar mounting step, the at least one pillar is mounted on a surface of a first substrate including a glass pane.