The invention provides a novel n-type thermoelectric conversion material which comprises low-toxic and abundant elements, and has excellent heat-resistance, chemical durability and the like, as well as high thermoelectric conversion efficiency, the thermoelectric conversion material comprises a metal oxynitride thermoelectric conversion material which has a composition represented by formula Ti1-xAxOyNz (wherein A is at least one element selected from the group consisting of transition metals of the 4th and 5th periods of the periodic table, and 0≦x≦0.5, 0.5≦y≦2.0, 0.01≦z≦0.6), and has an absolute value of thermoelectric power of at least 30 μV/K at 500° C. or above, and a novel n-type thermoelectric conversion material, a thermoelectric conversion element and a thermoelectric conversion module comprising the above metal oxynitride can also be provided.