provided is a method for manufacturing a flexible metal - clad laminate using a casting method , including : forming a first polyimide layer having a coefficient of linear thermal expansion of 25 ppm / k or less above a metal layer ; plasma - treating a surface of the first polyimide layer ; and forming a second polyimide layer having a coefficient of linear thermal expansion of 25 ppm / k or lower above the first polyimide layer . the flexible metal - clad laminate according to the present invention can have excellent adhesion between the polymer film and the metal conductive layer , a low dimensional change , and a low production cost , because of superior casting workability , even though the thickness of polyimide becomes increased .