A semiconductor photodetection element SP has a silicon substrate 21 comprised of a semiconductor of a first conductivity type, having a first principal surface 21a and a second principal surface 21b opposed to each other, and having a semiconductor layer 23 of a second conductivity type formed on the first principal surface 21a side; and charge transfer electrodes 25 provided on the first principal surface 21a and adapted to transfer generated charge. In the silicon substrate 21, an accumulation layer 31 of the first conductivity type having a higher impurity concentration than the silicon substrate 21 is formed on the second principal surface 21b side and an irregular asperity 10 is formed in a region opposed to at least the semiconductor region 23, in the second principal surface 21b. The region where the irregular asperity 10 is formed in the second principal surface 21b of the silicon substrate 21 is optically exposed.