The purpose of the present invention is to provide an antithrombotic material capable of enhancing safety in terms of low hemolytic toxicity and actualizing a high antithrombotic property persistently over an extended period of time. The prtesent invention provides an antithrombotic material furnished with a covering material including a polymer containing a compound selected from the group consisting of alkylene imine vinyl amine allyl amine lysine protamine and diallyl dimethyl ammonium chloride as a structural monomer and a sulfur atom containing anionic compound having anticoagulant activity and a base material the surface of which is covered by this covering material wherein the polymer bonds covalently with the base material and the abundance ratio of nitrogen atoms to the abundance of all atoms measured by X ray electron spectroscopy on the surface is 6.0 12.0 atom%.
