A pyroelectric detector includes a substrate, a support member and a pyroelectric detection element, which includes a capacitor, first and second reducing gas barrier layers, an insulating layer, a plug and a second electrode wiring layer. The first reducing gas barrier layer covers at least a second electrode and a pyroelectric body of the capacitor, and has a first opening that overlaps the second electrode in plan view. The insulating layer covers at least the first reducing gas barrier layer, and has a second opening that overlaps the first opening in plan view. The plug is disposed in the first and second openings and connected to the second electrode. The second electrode wiring layer is formed on the insulating layer and connected to the plug. The second reducing gas barrier layer is formed on the insulating layer and the second electrode wiring layer and covers at least the plug.