TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Device: The high-temperature portion includes a flow path for a high-temperature fluid, and the low-temperature portion includes a flow path for a cooling medium.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: a part of a total amount of the Ti (titanium), Zr (zirconium) and Hf (hafnium) is replaced by at least one of element selected from V (vanadium), Nb (niobium), Ta (tantalum), Cr (chromium), Mo (molybdenum), W (tungsten), Sc (scandium), Y (yttrium), U (uranium) or a lanthanoid element. A part of the Co (cobalt) is replaced by at least one of element selected from Mn (manganese), Fe (iron), Ni (nickel), Cu (copper), Ag (silver), Pd (palladium), Pt (platinum), Ru (ruthenium) or Os (osmium). A part of a total amount of the Sb and Sn (tin) is replaced by at least one element selected from Bi (bismuth), Pb (lead), Se (selenium), Te (tellurium) or Ge (germanium). A part of a total amount of the Sb and Sn is replaced by at least one element selected from Bi or Ge. The p-type thermoelectric element is composed of the thermoelectric material. The p-type thermoelectric element comprises several p-type thermoelectric elements and the n-type thermoelectric element comprises several n-type thermoelectric elements, and the p-type thermoelectric elements and the n-type thermoelectric elements are alternately disposed and connected in series with the first, second and third electrodes. Preferred Definitions:    r=value of greater than 0.1 and less than or equal to 0.3;    p=0.2-50.3;    q=0.25-50.3 or 0.2-0.3;    z=0.2-0.3.    EXAMPLE - Predetermined amounts of the respective materials were weighed to achieve the composition (Ti(0.25)Hf(0.25)Zr(0.5))30Co35(Sb(0.85)Sn(0.15))35, and were subjected to arc melting and the mother alloys were produced. The mother alloy was pulverized into a particle size of less than or equal to 45 mu m; alloy powder was hot-pressed 1350degrees C for 1 hour, and molded to obtain thermoelectric material having outer diameter of 15 mm and a thickness of 3 mm. The chip in a desired shaped was cut out and evaluated for thermoelectric characteristics such as Seebeck coefficient (alpha ), electric resistivity (rho ), and output factor (alpha 2/rho ). The material showed the powder X-ray diffraction having the diffraction peak mainly derived from the MgAgAs crystal phase. The material showed the properties as follows: Seebeck coefficient (mu V/K): 310; electric resistivity (mOmega .cm): 2.7; and output factor (mV/mK2): 3.7.