Abstract: The present invention relates to a pharmaceutical composition for preventing or treating autoimmune diseases or tumors, containing, as an active ingredient, a tricyclic compound represented by the following Chemical Formula 1 or a pharmaceutically acceptable salt thereof, and a health food composition for preventing or alleviating autoimmune diseases or tumors, containing the tricyclic compound as an active ingredient, wherein the tricyclic compound represented by Chemical Formula 1 has an excellent inhibitory activity against IRAK4, and thus can be usefully used for the prevention, treatment, or alleviation of autoimmune diseases or tumors.