The present disclosure relates to a solid-state imaging device, a manufacturing method thereof, and an electronic apparatus, in which both oblique light characteristics and sensitivity can be improved. The solid-state imaging device includes pixel array unit in which a plurality of pixels is two-dimensionally arranged in a matrix and multi-stage light shielding walls are provided between the pixels. The present disclosure is applicable to, for example, a back-illuminated type solid-state imaging device and the like.