To increase a detection output of a pyroelectric photodetector.
A pyroelectric photodetector comprises: a substrate 10; a support member 215 supported on the substrate; and a pyroelectric photodetecting element 251 formed in contact with the support member. The pyroelectric photodetecting element 251 includes a capacitor 230 having: a first electrode 234 provided on a support member side; a second electrode 236 provided facing the first electrode and having a smaller area in a planar view than the first electrode; a pyroelectric body 232 provided between the first electrode 234 and the second electrode 236. The pyroelectric photodetecting element 251 further includes a light absorption layer 270 formed on the capacitor. If an area of the light absorption layer in a planar view is regarded as a light receiving area Aa, and an area of the second electrode in a planar view is regarded as a capacitor area Ac, Aa/Ac satisfies 2.0<Aa/Ac<49.0.
Takekoshi Noboru
Yasushi Kuroda