The present invention relates to a novel epitope that converts T cell to type 1 helper T (TH1) cell. Specifically, the present invention relates to an epitope constituting the 56th to 65th amino acids (SEQ ID No. 2) of extracellular domain (ECD) of activation-inducible tumor necrosis factor receptor (AITR), an antibody recognizing the epitope, a polynucleotide encoding the epitope, a polynucleotide encoding the antibody, an expression vector comprising the polynucleotide encoding the epitope or antibody, a transformant introduced with the vector, a composition comprising the antibody for converting T cell to TH1 cell and a method for converting T cell to TH1 cell, a pharmaceutical composition comprising the antibody for preventing or treating cancer, a method for treating cancer using the antibody, a composition comprising the antibody for enhancing immunity, and a method for enhancing immunity using the antibody.