A thermoelectric conversion material of the present disclosure is a p-type thermoelectric conversion material which includes an alloy containing Mg and Bi as a main phase and which contains carbon. The thermoelectric conversion material includes, for example, a Mg3(Sb,Bi)2-based alloy as the main phase. An atomic percentage of Bi included in the main phase is greater than or equal to an atomic percentage of Sb included in the main phase. The thermoelectric conversion material satisfies, for example, 0.01 at %≤CC≤1.2 at %, where CC represents a content ratio of carbon in the thermoelectric conversion material.