To provide a solid-state imaging element capable of further improving reliability. Provided is a solid-state imaging element including at least a first photoelectric conversion section, and a semiconductor substrate in which a second photoelectric conversion section is formed, in this order from a light incidence side, in which the first photoelectric conversion section includes at least a first electrode, a photoelectric conversion layer, a first oxide semiconductor layer, a second oxide semiconductor layer, and a second electrode in this order, and a film density of the first oxide semiconductor layer is higher than a film density of the second oxide semiconductor layer.