A polymeric fluorescent substance exhibiting visible fluorescence in the solid state, having polystyrene reduced number average molecular weight of 1.times.10.sup.3 to 1.times.10.sup.8, and comprising one or more repeating units of following formula (1), ##STR00001## wherein Ar.sub.1 and Ar.sub.2 each independently represent an arylene group or the like; Ar.sub.3 represents an aryl group or the like having one or more substituents of formula (2) as nuclear substitution; X represents --CR.sub.1.dbd.CR.sub.2-- or --C.ident.C--; and n is 0 or 1, --Y--Ar.sub.4 (2) wherein Ar.sub.4 represents an aryl group or the like; and Y represents --CR.sub.3.dbd.CR.sub.4-- or --C.ident.C--. The triarylamine type polymeric fluorescent substance is excellent in quantum yield of fluorescence and in light emitting efficiency when made into a device.