Polymeric fluorescent substance and polymer light-emitting device

A polymer fluorescent substance which emits fluorescence in solid state, has a number-average molecular weight in terms of polystyrene of 1×104 to 1×108, has at (least one repeating unit of the following general formula (1) and in which the ratio of the hole drift mobility uh to the electron drift mobility μe of said polymer fluorescent substance is from 0.1 to 10:

• wherein Ar1 is a divalent group forming carbon-carbon bonds with adjacent two groups respectively, the divalent group being an arylene group having 6 to 60 carbon atoms participating (in conjugation or a heterocyclic compound group having 3 to 60 carbon atoms and 1 to 3 hetero atoms participating in conjugation, and the arylene group and heterocyclic compound group may be optionally substituted;
• each of R1 and R2 independently represents a group selected from the group consisting of a hydrogen atom, linear, branched or cyclic alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 60 carbon atoms, heterocyclic compound groups having 3 to 60 carbon atoms and a cyano group, and the aryl group and heterocyclic compound group may be optionally substituted;
• and j is 0 or 1.