Light detection device and electronic device

An electronic device comprising a light detection device, the light detection device comprising:

• a first substrate portion having a pixel configured to photoelectrically convert incident light;
• a second substrate portion stacked on a surface of the first substrate portion opposite to a surface on which the light is incident and having a readout circuit configured to output a pixel signal based on charge output from the pixel to a signal line;
• and
• a through via configured to connect the first substrate portion and the second substrate portion,
• the pixel having a floating diffusion configured to temporarily retain charge generated by photoelectric conversion,
• the readout circuit having
• a first pixel transistor connected to the floating diffusion through the through via, and
• a second pixel transistor connected to the first pixel transistor and the signal line, the through via being provided, in plan view, between a contact portion provided at a gate electrode of the first pixel transistor and a contact portion provided at a gate electrode of the second pixel transistor in a region of the pixel and in a position shifted in a second direction orthogonal to a first direction in which the contact portion of the first pixel transistor and the contact portion of the second pixel transistor are provided.