A method for manufacturing metallized aluminum nitride substrate. The method includes: Step A for forming a high-melting point metal layer over a sintered aluminum nitride substrate; Step B for forming over the high-melting point metal layer an intermediate metal layer of at least one selected from the group of: nickel, copper, copper-silver, copper-tin, and gold by plate processing; and Step C for forming a surface metal layer containing silver as a main component over the intermediate metal layer by coating a silver paste whose glass component content is 1 mass % or less and firing under nonoxidizing atmosphere. By this method, it is capable of forming a glass component-free silver layer which is adhered at a high degree of adhesion strength onto the high-melting point metal layer formed over the aluminum nitride substrate as a top face by thick-film method using a silver paste which makes thick-membrane forming easier.