An photodetection device according to an embodiment includes: a pixel including at least one cell, the at least one cell including an avalanche photodiode and a resistor connected in series to the avalanche photodiode; a voltage source configured to apply voltage to the cell of the pixel; and a temperature detecting circuit including a temperature detecting element configured to detect a temperature of the pixel, wherein the temperature detecting element includes: a photodiode having the same structure as the avalanche photodiode; and a light shielding structure disposed on an upper surface of the photodiode.