A process for production of polyimide molded bodies which comprises a step in which a polyimide resin powder obtained by polymerization and imidation of p-phenylenediamine with 3,3,4,4′-biphenyltetracarboxylic acid, its ester or its dianhydride and 2,3,3′,4′-biphenyltetracarboxylic acid, its ester or its dianhydride is molded at a pressure of approximately 800-5,000 kgf/cm2, a step in which the pressurized body is subjected to calcination at about 450-550° C. under low pressure, a step in which the calcined molded body is vacuum encapsulated into a metal capsule, and a step in which the encapsulated molded body is isotropically subjected to hot compression at approximately 460-550° C. in an inert gas atmosphere such as argon. The polyimide molded bodies obtained thereby have a density in the range of 1.44-1.38 g/cm3.