The present invention relates to a pharmaceutical composition for preventing or treating atopic dermatitis, the pharmaceutical composition including, as an active ingredient, X-shaped DNA (XL-DNA) formed by complementary binding of oligonucleotides having nucleotide sequences of SEQ ID NO: 1 to SEQ ID NO: 4. When the pharmaceutical composition is subcutaneously injected into an animal model of atopic dermatitis, effects of easing skin lesions, such as erythema, bleeding and edema, and the like, and ear edema, and reducing expression of immunoglobulin E (IgE) are exhibited. In this regard, the composition can be used as a pharmaceutical composition, a health food, or a cosmetic for atopic dermatitis.
