An object of the present invention is to provide a hydrophilic polymer compound which can inhibit both of the blood coagulation reactions in the primary hemostasis stage in which platelets are involved and in the coagulation thrombus formation stage in which blood coagulation factors are involved, which hydrophilic polymer compound can be firmly immobilized on the surface of medical devices or medical materials, in the state retaining the anticoagulant activity. The present invention provides a hydrophilic polymer compound comprising a polymer compound which inhibits platelet adhesion, and a compound that inhibits blood coagulation reaction, bound to said polymer compound.
