A pixel in which both phase difference detection and image generation are performed can be implemented with a more simple structure. Each of a plurality of pixels two-dimensionally arranged in a matrix shape includes a first photoelectric conversion unit and a second photoelectric conversion unit both configured to photoelectrically convert light entering via one micro lens. A first reading circuit reads an electric charge generated at the first photoelectric conversion unit and a second reading circuit reads an electric charge generated at the second photoelectric conversion unit. A transistor connects a first electric charge holding unit included in the first reading circuit to a second electric charge holding unit included in the second reading circuit. The present technology is applicable to, for example, a solid-state imaging device that detects a phase difference.