PURPOSE: To provide a thermoelectric conversion element material for greatly improving a performance index of a heat generation device wherein Nernst effect to generate an electric potential difference in a vertical direction in both a temperature gradient and a magnetic field.

CONSTITUTION: A thermoelectric conversion element material is used for heat power generation by Nernst effect for picking up a voltage in a direction perpendicular each other in both a magnetic field and a temperature gradient in a thermoelectric conversion material by heating one side of a thermoelectric conversion element material and cooling the other side, by generating a temperature gradient in an inside thereof and by applying a magnetic field in a direction practically perpendicular to a temperature gradient. It comprised at least one selected from a group consisting of HgSe, HgTe, InSb and Cd As.