Solid-state imaging device and electronic apparatus

Spectral performance in a wide wavelength range is improved. A solid-state imaging device according to an embodiment includes: a pixel array unit in which a plurality of photoelectric conversion elements (PD) are arranged in a two-dimensional lattice form; a plurality of diffraction gratings provided corresponding one-to-one to light-receiving surfaces of the plurality of photoelectric conversion elements; and pixel circuits configured to generate pixel signals on the basis of charge accumulated in the photoelectric conversion elements, wherein a period of a first diffraction grating positioned at a first imaging height is different from a period of a second diffraction grating positioned at a second imaging height different from the first imaging height.