A thermoelectric semiconductor element is disclosed which is particularly low in toxicity and inexpensive. The element is mainly composed of a complex oxide comprising strontium and titanium. An oxide semiconductor possessing oxygen deficiency is used as the n-type element. According to the invention, as compared with a thermoelectric semiconductor element for thermoelectric cooling using a conventional Bi-Te thermoelectric semiconductor which is particularly toxic due to addition of Se or the like, the toxicity of the n-type semiconductor element part is lowered, and a thermoelectric semiconductor element excellent in performance is obtained.