PROBLEM TO BE SOLVED: To provide methods for treating erosive polyarthritis.SOLUTION: The methods for treating erosive polyarthritis comprising administering a TNFα antibody, or antigen-binding portion thereof. The invention also describes a method for testing the efficacy of a TNFα antibody, or antigen-binding portion thereof.【課題】びらん性多発性関節炎の治療法の提供。【解決手段】TNFα抗体又はその抗原結合部分を投与することを含むびらん性多発性関節炎の治療法及び、TNFα抗体又はその抗原結合部分の有効性を検査する方法。【選択図】なし