To provide a polyimide/metal laminate and a flexible printed wiring board suitable as an electric machinery circuit operated without damaging function even under a high temperature and high humidity environment.

A partially cured and/or partially dried polyamic acid film is immersed in water or an aqueous solution or coated with water or the aqueous solution and, thereafter, a polyamic acid is converted to a polyimide to obtain a polyimide film. This polyimide film and a metal layer are laminated to obtain the polyimide/metal laminate. The adhesive strength of the polyimide film and the metal layer per a pattern width of 1 mm after exposed to a 121°C/100% RH environment for 96 hr is not less than 60% as compared with that before exposure.