A glass panel unit includes: a first glass pane; a second glass pane facing the first glass pane; a frame member; an evacuated space; and a gas adsorbent. The frame member hermetically bonds the first glass pane and the second glass pane. The evacuated space is surrounded with the first glass pane, the second glass pane, and the frame member. The gas adsorbent is placed in the evacuated space. The gas adsorbent contains a getter material. The getter material contains a plurality of particles of a zeolite crystal. At least one particle accounting for a half or more of a total weight of the plurality of particles has a particle size equal to or greater than 200 nm. An activable temperature of the at least one particle is equal to or lower than 400° C.