PURPOSE: To provide a polyimide precursor compound which is easy to be poured in from a vessel for transport or storage and which is formed by mixing a specific compound with a polyamic acid produced through reaction of an aromatic diamine with a tetracarboxylic acid dianhydride followed by irradiation with microwaves.

CONSTITUTION: An aromatic tetracarboxylic acid dianhydride (for example, pyromellitic acid dianhydride, Component-(i)) is reacted with an aromatic diamine, Component-(ii), such as 2,2-bis[4-(3-aminophenoxy) phenyl]hexafluoropropane so that a polyamic acid is produced. The obtained substance (A) in an amount 2-20wt.% is dissolved in 15-25wt.% inactive solvent (for example, dimethylformamide) (B), and thereto 25-40wt.% aromatic tetracarboxylic acid diester (C) and 25-50wt.% Component (ii) are added, followed by irradiation with microwaves in a dosage enough to generate fluidity without causing any chemical reaction so that an intended compound is obtained.