In a radiant heat sensor, first and second thermoelectric members are alternately arrayed one by one in a direction along a first surface of a plate-shaped member so as to be separated from each other, and each of the first and second thermoelectric members configure a portion of the first surface. First conductor patterns extend the first surface, disposed on the first surface so as to span a single first thermoelectric member and a single second thermoelectric member that are adjacent to each other, and configure hot contact portions between the first and second thermoelectric members. Second conductor patterns extend along the first surface, disposed on the first surface so as to span a single first thermoelectric member and a single second thermoelectric member that are adjacent to each other, and configure cold contact portions between the first and second thermoelectric members.