A positive photosensitive polyimide resin composition which comprises 100 parts by weight of an organic solvent-soluble polyimide resin and 1-100 parts by weight of an .omicron.-quinonediazide compound, said polyimide resin being composed of the repeating units represented by formulas [I] and [II] below ##STR1## (where R.sub.1 is a divalent organic group to constitute a diamine which has one or more groups of at least one kind selected from the group consisting of phenolic hydroxyl group, carboxyl group, thiophenol group, and sulfonic group; R.sub.3 is a divalent organic group having no phenolic hydroxyl group, carboxyl group, thiophenol group, and sulfonic group; and R.sub.2 and R.sub.4 each are a tetravalent organic group constituting a-tetracarboxylic acid and a derivative thereof when R.sub.1 has one or more groups of at least one kind selected from the group consisting of carboxyl group and sulfonic group and has no phenolic hydroxyl group and thiophenol group, or R.sub.2 and R.sub.4 each are a tetravalent organic group constituting a tetracarboxylic acid and a derivative thereof composed of four carbonyl groups which are not attached directly to the aromatic ring when R.sub.1 has a phenolic hydroxyl group and/or thiophenol group) with the molar percentage (a) of the repeating units represented by formula [I] being in the range of 1 mol %.ltoreq.a.ltoreq.90 mol % and the molar percentage (b) of the repeating units represented by formula [II] being in the range of 10 mol % .ltoreq.b.ltoreq.99 mol %, and having a reduced viscosity of 0.05-3.0 dl/g (measured at a concentration of 0.5 g/l in N-methylpyrrolidone at 30.degree. C.).