Light detection device

A photodetecting device comprising:

• a semiconductor photodetecting element including a semiconductor substrate in which a photodiode array including a plurality of pixels is formed, the semiconductor substrate having a first principal surface and a second principal surface opposing each other;
• and
• a mount substrate disposed to oppose the semiconductor photodetecting element, and having a third principal surface opposing the second principal surface of the semiconductor substrate and a fourth principal surface opposing the third principal surface,
• wherein the semiconductor substrate includes a first region in which the plurality of pixels are disposed and a second region located inside the first region to be surrounded by the first region when viewed from a direction in which the first principal surface and the second principal surface oppose each other,
• a through-hole penetrating through the semiconductor substrate is formed in the second region of the semiconductor substrate, and
• a first electrode disposed on a side of the first principal surface of the semiconductor substrate and electrically connected to the plurality of pixels and a second electrode disposed on a side of the third principal surface of the mount substrate are connected to each other via a first wire inserted through the through-hole.