Disclosed is a thermoelectric material comprising a main phase which is represented by the following composition formula and having an MgAgAs-type crystalline structure:(Ta1Zrb1Hfc1)xCoySb100-x-y wherein 0<a1<1, 0<b1<1, 0<c1<1, a1+b1+c1=1, 30≦x ≦35, and 30≦y≦35.