The present disclosure relates to a solid-state imaging device, a signal processing method therefor, and an electronic apparatus enabling sensitivity correction in which a sensitivity difference between solid-state imaging devices is suppressed.The solid-state imaging device includes a pixel unit in which one microlens is formed for a plurality of pixels in a manner such that a boundary of the microlens coincides with boundaries of the pixels. The correction circuit corrects a sensitivity difference between the pixels inside the pixel unit based on a correction coefficient. The present disclosure is applicable to, for example, a solid-state imaging device and the like.