The invention provides a metallic pattern forming method comprising: forming a region in which a graft polymer, that directly bonds to a surface of a base material that includes a polyimide and has a functional group that interacts with either an electroless plating catalyst or a precursor thereof, is generated in a pattern shape; imparting either an electroless plating catalyst or a precursor thereof and electroless plating so as to form a metallic film in the pattern shape, wherein the polyimide has at least one structural unit represented by the following Formula (1) or Formula (2) and has a polymerization initiating site in a skeleton thereof. ##STR00001## R.sup.1 represents a bivalent organic group. R.sup.2 is represented by one of Formulae (3) to (6). ##STR00002## R.sup.3, R.sup.4, R.sup.5 and R.sup.6 independently represents a bivalent organic group.