A dimming device 700 includes a first substrate 711 and a second substrate 712, a first electrode 731 formed on top of the first substrate 711, a dimming layer 720 formed on top of the first electrode 731, a second electrode 732 formed on top of at least the dimming layer 720, a moisture-retaining member 741 that covers at least the second electrode 732 and faces the second substrate 712, and sealing members 733, 734, 735, and 736 provided in an edge portion of the first substrate 711, and a moisture-retaining member extending portion 743 that extends from the moisture-retaining member 741 is disposed between the sealing member and the second substrate 712, and a thickness of the moisture-retaining member extending portion 743 is thinner than a thickness of the moisture-retaining member 742 in a central portion of the dimming device 700.