PHOTOELECTRIC CONVERSION DEVICE

Provided is a photoelectric conversion device for detecting the spot size of incident light. A photoelectric conversion device 1 is provided with: a photoelectric conversion element 20 including a photoelectric conversion substrate provided with two main surfaces, and including a first sensitivity section 21 and second sensitivity sections 22; and scanning units 60, 70 that relatively scan incident light on the main surfaces of the photoelectric conversion element 20. When a sensitivity region that appears on a main surface of the first sensitivity section 21 is defined as a first sensitivity region and sensitivity regions that appear on a main surface of the second sensitivity sections 22 are defined as second sensitivity regions, the first sensitivity region receives at least a part of the light incident on the main surface during scanning by the scanning units 60, 70, and has a pattern in which, in accordance with enlargement of an irradiation region which is irradiated with incident light on the main surface, the proportion of the first sensitivity region with respect to the second sensitivity regions in the irradiation region is decreased.