A thermoelectric conversion material has a composition represented by General Formula LkRrTt−mMmSbx. Here, L includes at least one element selected from rare earth elements. R includes two or more elements selected from the group consisting of alkali metal elements, alkali earth metal elements, Group 4 elements, and Group 13 elements. T includes at least one element selected from Fe and Co. M includes at least one element selected from the group consisting of Ru, Os, Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au. In addition, 0.50≤k≤1.00, 0.1≤r≤0.5, 3.0≤t−m≤5.0, 0≤m≤0.5, 10.0≤x≤11.5, and x/t