A plastic substrate for display, having little coloration and excellent in optical characteristics, heat resistance, resistance to thermal coloration and mechanical properties, and a display element using the same are provided. The plastic substrate for display comprises a fumaric acid diester resin which comprises 60 mol % or more of a fumaric acid diester residue unit represented by the following formula (1): ##STR00001## wherein R.sub.1 and R.sub.2 each independently represent a branched alkyl group or a cyclic alkyl group, having 3 12 carbon atoms, and has a number average molecular weight of 1,000 500,000 as determined by a gel permeation chromatography and converted into standard polystyrene, the substrate having a thickness 30 600 .mu.m.