PROBLEM TO BE SOLVED: To provide antibodies that specifically bind to tissue factor pathway inhibitor and reduce clotting time of blood.SOLUTION: The invention provides monoclonal antibodies that specifically bind to Kunitz 2 (K2) domain of TFPI, which antibodies specifically bind to an epitope of the domain comprising specified residues. Such an antibody can neutralize TFPI inhibition of membrane bound FVIIa/TF/FXa by at least 55% as measured in an FVIIa/TF/FXa inhibitor assay, when TFPI is saturated with the antibody. Such antibodies have utility in the treatment of subjects with a coagulopathy.【課題】組織因子経路阻害因子(TFPI)と特異的に結合し、かつ血液の凝固時間を低減する抗体を提供する。【解決手段】TFPIのKunitz 2(K2)ドメインと特異的に結合できるモノクローナル抗体であって、該ドメインの特定の残基を含むエピトープと特異的に結合できる抗体。TFPIが前記抗体で飽和されている場合に、FVIIa/TF/FXa阻害因子アッセイにおいて測定して、膜結合FVIIa/TF/FXaのTFPI阻害を、少なくとも55%中和出来てよい。該抗体は、凝血異常の対象の治療において有用である。【選択図】なし