COOLING STRUCTURE FOR PHOTOELECTRIC CONVERSION ELEMENT

This cooling mechanism for a surface-mounted-type photoelectric conversion element is provided on a circuit board (109) to which a surface-mounted-type photoelectric conversion element (100), which has a signal terminal that is connected to inner wiring and a terminal for fixation that is not connected to the inner wiring on a back surface thereof, is mounted, the cooling mechanism has a front-surface-side copper foil pattern (104) to which the terminal for fixation is connected, a back-surface-side copper foil pattern (107), and a through-hole via (10) which connects the copper foil patterns, a cooling member (108) which is fixed to the circuit board so as to have contact with the back-surface-side copper foil pattern, and which cools the back-surface-side copper foil pattern.