The present disclosure relates to a solid-state imaging device and an electronic device that are configured to suppress the occurrence of noise and white blemishes in an amplification transistor having an element separation region which is formed by ion implantation. An amplification transistor has an element separation region formed by ion implantation. A channel region insulating film which is at least a part of a gate insulating film above a channel region of the amplification transistor is thin compared to a gate insulating film of a selection transistor, and an element separation region insulating film which is at least a part of a gate insulating film above the element separation region of the amplification transistor is thick compared to the channel region insulating film. The present disclosure can be applied to, for example, a CMOS image sensor, etc.