The present disclosure relates to a solid-state imaging element capable of suppressing stray light with respect to a charge storage unit such as an FD, and an electronic device. According to an aspect of the present disclosure, a solid-state imaging element constituted by many pixels includes a photoelectric conversion unit formed for each of the pixels and that converts incident light into a charge; a charge storage unit that temporarily holds the converted charge; and a first light shielding unit formed between the pixels and having a predetermined length in a thickness direction of a substrate. The charge storage unit is formed below a cross portion where the first light shielding unit formed between pixels adjacent to each other in a longitudinal direction crosses the first light shielding unit formed between pixels adjacent to each other in a lateral direction. The present disclosure can be applied to, for example, a backside irradiation type CMOS image sensor.