A thermoelectric conversion element includes a p-type metal thermoelectric conversion material containing a metal as its main constituent, an n-type oxide thermoelectric conversion material containing an oxide as its main constituent, and a composite oxide insulating material containing a composite oxide as its main constituent. The p-type metal thermoelectric conversion material and the n-type oxide thermoelectric conversion material are directly bonded in a region of a junction plane between the p-type metal thermoelectric conversion material and the n-type oxide thermoelectric conversion material, and the p-type metal thermoelectric conversion material and the n-type oxide thermoelectric conversion material are bonded to each other with the composite oxide insulating material interposed therebetween so as to define a pn conjunction pair in the other region of the junction plane. A perovskite-type oxide is used as the n-type oxide thermoelectric conversion material.