A thermoelectric conversion material having excellent thermoelectric performance over a wide temperature range, and a thermoelectric conversion module providing excellent junctions between thermoelectric conversion materials and electrodes. An R-T-M-X-N thermoelectric conversion material has a structure expressed by the following formula: RrTt-mMmXx-nNn (0≤r≤1, 3≤t−m≤5, 0≤m≤0.5, 10≤x≤15, 0≤n≤2), where R represents three or more elements selected from the group consisting of rare earth elements, alkali metal elements, alkaline-earth metal elements, group 4 elements, and group 13 elements, T represents at least one element selected from Fe and Co, M represents at least one element selected from the group consisting of Ru, Os, Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au, X represents at least one element selected from the group consisting of P, As, Sb, and Bi, and N represents at least one element selected from Se and Te.