A nitrogen-containing thermoelectric material, which has an element composition represented by: Al.sub.zGa.sub.yIn.sub.xM.sub.uR.sub.vO.sub.sN.sub.t (A) or Al.sub.zGa.sub.yIn.sub.xM.sub.uR.sub.vD.sub.wN.sub.m (B) (wherein M represents a transition element; R represents a rare earth element; D represents at least one element selected from elements of the Group IV or II; 0.ltoreq.z.ltoreq.0.7, 0.ltoreq.y.ltoreq.0.7, 0.2.ltoreq.x.ltoreq.1.0, 0.ltoreq.u.ltoreq.0.7, 0.ltoreq.v.ltoreq.0.05, 0.9.ltoreq.s+t.ltoreq.1.7, 0.4.ltoreq.s.ltoreq.1.2, 0.ltoreq.w.ltoreq.0.2, and 0.9.ltoreq.m.ltoreq.1.1; and x+y+z=1), and has an absolute value of a Seebeck coefficient of 40 .mu.V/K or more at a temperature of 100.degree. C. or more. These thermoelectric materials comprise elements having low toxicity, are excellent in a heat resistance, a chemical resistance and the like, and have a high thermoelectric transforming efficiency.