Thermoelectric conversion materials, expressed by the following formula: Bi1-xMxCu1-wOa-yQ1yTeb-zQ2z. Here, M is at least one element selected from the group consisting of Ba, Sr, Ca, Mg, Cs, K, Na, Cd, Hg, Sn, Pb, Mn, Ga, In, Tl, As and Sb; Q1 and Q2 are at least one element selected from the group consisting of S, Se, As and Sb; x, y, z, w, a, and b are 0≦x 0. These thermoelectric conversion materials may be used for thermoelectric conversion elements, where they may replace thermoelectric conversion materials in common use, or be used along with thermoelectric conversion materials in common use.