Pyroelectric detection device, including at least: a substrate; a membrane arranged on the substrate; a pyroelectric detection element arranged on the membrane or forming at least one part of the membrane, and including at least one portion of pyroelectric material arranged between first and second electrodes; a cavity passing through the substrate, emerging opposite a part of the membrane which forms a bottom wall of the cavity, and including side edges formed by the substrate; an element for stiffening the membrane arranged in the cavity, partially filling the cavity, made integral with the side edges of the cavity at at least two distinct anchoring regions, and arranged against the membrane.