The present invention relates to a polyimide resin surface modifier which modifies the surface of a polyimide resin to permit easy absorption of metal ions, and a surface-modifying method for polyimide resins using the same. The surface modifier contains an alkali component, an organic solvent having hydroxy groups and a boiling point of 120° C. or higher, and a water content of 0-10% by weight. The surface-modifying method includes a printing process wherein a predetermined pattern is printed on the surface of a polyimide resin substrate using the polyimide resin surface modifier, an organic solvent-removing process wherein an organic solvent in the polyimide resin surface modifier pattern-printed on the surface of said polyimide resin substrate is removed and a water-treatment process wherein said polyimide resin surface modifier after removing the organic solvent is brought into contact with water.