A pyroelectric detector includes a substrate, a support member, a spacer member, and a pyroelectric detecting element. The spacer member supports the support member over the substrate with a cavity part being formed therebetween. The pyroelectric detecting element includes a first electrode mounted on the support member, a second electrode, and a pyroelectric body between the first and second electrodes. The first electrode includes a first region on which the pyroelectric body is layered, and a second region protruding from the first region in plan view. The support member includes an insulating layer, a first wiring layer disposed on the second surface side of the insulating layer, and a first plug passing through the insulating layer at a position where the first wiring layer and the second region of the first electrode overlap in plan view to connect the first wiring layer with the first electrode.