A method of producing porous polyimide resin that enables pores to be formed in a precursor of polyimide resin, with its form of microphase-separated structure wherein a dispersive compound is dispersed in the precursor of polyimide resin being kept unchanged, so as to provide significantly reduced dielectric constant and also provide improvement in mechanical strength and heat resistance, and the porous polyimide resin produced in the same producing method. A coating comprising porous polyimide resin is formed by applying resin solution comprising a precursor of polyimide resin and a dispersive compound and then drying a solvent, to form a coating in which the dispersive compound is dispersed in the precursor of polyimide resin; extracting the dispersive compound from the coating for removal to make the precursor of the polyimide resin porous; and imidizing the coating after preheated in a temperature range of 190-250 C.