The polyimide film of the present invention is produced in the following
manner: polyamic acid made of a combination of a specific acid anhydride
constituent and a specific diamine constituent are heated under a
low-pressure circumstance for heat imidation, and the obtained imide is
dissolved again in a solvent to be polyimide solution, then the polyimide
solution is formed to be a film. In this manner, it is possible to
provide a polyimide film essentially transparent and colorless, and has
sufficient toughness to prevent occurrences of a crack or a break when
the film is folded and creased by hand.