PURPOSE: A polymer bonding with albumin that is composed of a polyaddition polymer from a polyamine and a polyepoxy compound in which a specific amount of albumin is included, thus being suitably used as a medical material because of its high blood compatibility and antithrombotic property.

CONSTITUTION: A polyamine of formula (n is 1W10) and a polyepoxy compound such glycerol diglycidyl ether are combined preferably at a ratio of 1.05W1.5 equivalent of epoxy group to 1 equivalent of amino group and the addition reaction is effected at 20W30°C to give a water-insoluble polymer. The polymer is immersed in an aqueous solution containing, preferably 0.5W5wt% of albumin to effect reaction at 5W35°C for 1minW1hr so that more than 20wt% of albumin is included, whereby the objective polymer is obtained.