A thermoelectric conversion element (1) having, on a substrate (12), a first electrode (13), a thermoelectric conversion layer (14), and a second electrode 15, wherein a nano conductive material and a low band gap material are contained in the thermoelectric conversion layer (14); an article for thermoelectric power generation and a power supply for a sensor using the thermoelectric conversion element (1); and a thermoelectric conversion material containing the nano conductive material and the low band gap material.