Provided are a sensor chip and an electronic device for which the enhancement of the characteristics of SPAD pixels each including an avalanche photodiode element has been achieved. The sensor chip includes a pixel array section including a pixel area in which a plurality of pixels is arranged in rows and columns, an avalanche photodiode element that amplifies a carrier by a high electric field area provided for the each of the pixels, an inter-pixel separation section that insulates and separates the each of the pixels from another pixel adjacent to the each of the pixels in a semiconductor substrate in which the avalanche photodiode element is formed, and a wiring that is arranged in a wiring layer laminated on a surface being opposite to a light receiving surface of the semiconductor substrate in such a way as to cover at least the high electric field area. The pixel array section includes a dummy pixel area located near a peripheral edge of the pixel area, and a cathode electric potential and an anode electric potential of the avalanche photodiode element that is arranged in the dummy pixel area are a same electric potential, or at least one of the cathode electric potential and the anode electric potential is in a floating state.