A method of producing a medical device having a substrate and a hydrophilic polymer layer, including the steps of: pretreating the substrate by placing the substrate in an alkali solution and heating the substrate at a temperature ranging from 50° C. to 100° C.; and heating a solution containing the pretreated substrate, a hydrophilic polymer having an acidic group and a hydroxyalkyl group, and an organic acid at a temperature ranging from 50° C. to 100° C. Provided is a simple method of producing a medical device imparted with hydrophilicity excellent in durability.