To provide a preventive or therapeutic agent for thrombosis.A human monoclonal antibody that specifically binds to human FXIII-A or a functional fragment of said human monoclonal antibody that specifically binds human FXIII-A.Selection drawing None【課題】血栓症の予防または治療薬の提供。【解決手段】ヒトFXIII-Aに特異的に結合するヒトモノクローナル抗体、またはヒトFXIII-Aに特異的に結合する前記ヒトモノクローナル抗体の機能的断片。【選択図】なし