The semiconductor photodetector

The present invention provides a semiconductor light detector, substantially reduced by comparison with the conventional multiplication noise and dark noise, thereby detecting a feeble light, including random light. The semiconductor photodetector having at least one unit pixel, the unit pixel has a photoelectric converting portion, a charge accumulation unit, and a detection circuit. A photoelectric conversion unit performs photoelectric conversion of incident light, and has a charge of the charge by multiplying multiplication avalanche multiplication region. Charge accumulation portion connected to the photoelectric conversion portion, accumulated signal charges from the photoelectric conversion portion. Detection circuit charge accumulation portion connected to the charge accumulation portion of the accumulated charge into a voltage signal, after amplified by the amplifying unit output.