Abstract: A thermoelectric conversion substrate includes: an insulating substrate including a first surface on one side in a thickness direction of the insulating substrate and a second surface on an opposite side; a plurality of thermoelectric conversion units, each including a first thermoelectric member, a second thermoelectric member, and a first electrode that electrically connects the first thermoelectric member and the second thermoelectric member; and a second electrode. The insulating substrate includes at least one core insulating layer. The second electrode electrically connects the first thermoelectric member of one of the thermoelectric conversion units and the second thermoelectric member of another of the thermoelectric conversion units. The thermoelectric conversion units are electrically connected in series in a manner that the first thermoelectric member and the second thermoelectric member are alternately arranged.