Composition for preventing or treating autoimmune disease, using complex of metformin and statin

The present invention relates to a composition for preventing or treating autoimmune diseases, using a complex containing metformin, statin and, optionally, Coenzyme Q10. According to the present invention, a pharmaceutical composition for preventing or treating autoimmune diseases, which is the complex containing metformin, statin and, optionally, Coenzyme Q10, as active ingredients, can effectively inhibit the generation of inflammatory cytokines, can inhibit the generation of antibody-producing B cells or can reduce the activity thereof, has effects of inhibiting osteoclast differentiation and inhibiting joint destruction, and exhibits a remarkable effect of inhibiting the generation of foam cells, which generate artherosclerotic plaque progenitor cells, and thus can be useful as an agent for treating immunological diseases including autoimmune diseases.