According to an aspect, a light adjustment device includes: a panel unit in which a plurality of light adjustment panels are stacked in a first direction, the light adjustment panels each including a first substrate and a second substrate, the first substrate including at least two terminal groups each including a plurality of terminals that are capable of being coupled to one flexible printed circuit board, the second substrate overlapping with the first substrate; and a plurality of flexible printed circuit boards each of which is coupled to one of the terminal groups of a corresponding one of the light adjustment panels. A plurality of the terminal groups are arranged in a second direction intersecting the first direction when the panel unit is viewed in the first direction, and the flexible printed circuit boards do not overlap with one another when viewed in the first direction.