The present technology relates to a solid-state imaging device capable of suppressing deterioration in dark characteristics, and an electronic apparatus. The present invention is provided with: a photoelectric conversion section that performs photoelectric conversion; a charge retaining section that temporarily retains electric charge converted by the photoelectric conversion section; and a first trench formed in a semiconductor substrate between the photoelectric conversion section and the charge retaining section, the first trench being higher than the photoelectric conversion section in a depth direction of the semiconductor substrate. Alternatively, the first trench is lower than the photoelectric conversion section and higher than the charge retaining section in the depth direction of the semiconductor substrate. The present technology can be applied to, for example, a back-illuminated CMOS image sensor.