NOVELTY - The thermoelectric conversion material comprises a structure containing a complex oxide of specific formula. The structure has affinity with respect to ytterbium-iron oxide layer. The complex oxide comprises specific elements (A-C).    USE - As thermoelectric element, e.g. used in devices such as solar power generating device, electrical power generating device which generates power from factory exhaust heat or motor vehicle exhaust heat, for cell of optical detection element, laser diode, field effect transistor, photomultiplier tube, spectrophotometer, column chromatography, refrigerator and for electrical power unit of clocks.    ADVANTAGE - The novel thermoelectric conversion material has high and stable thermoelectric property at high temperature, electrical conductivity, excellent performance index, durability and low toxicity. It is manufactured simply and easily, and operates stably at high temperature. Further, it is inexpensive, and does not contain negative load.    DETAILED DESCRIPTION - The thermoelectric conversion material comprises a structure containing complex oxide of formula: ABOy(CO)m.    A = element such as lanthanoids, group IIIb element, scandium and/or yttrium;    B = group IIIb element and/or iron;    C = bivalent element, such as zinc, group IIa element, 3d transition metal element, 4d transition metal element and/or 5d transition metal element;    y = 2-4; and    m = 1-19.    The structure has affinity with respect to ytterbium-iron oxide (YbFe2O4) layer. At least one type of substituted element (I) chosen from group IVa element, substitutes 0.001-20 atomic% of element (A) and/or element (B). At least one type of substituted element (II) chosen from group IIIa element and group IIIb element, substitutes 0.001-20 atomic% of element (C). The element (C) is preferably zinc.    An INDEPENDENT CLAIM is included for manufacture of the above thermoelectric conversion material.    DESCRIPTION OF DRAWING(S) - The figure shows relationship between temperature, and Seebeck coefficient(S), electrical conductivity (sigma) and output factor (PF), of different complex oxides. (Drawing includes non-English language text).