The paper presents the investigation of the poly(3,3’-phthalidylidene-4,4’-biphenylylene) (PPB) film electroluminescence (EL). EL was found to be of threshold origin, the threshold being 20 B. The voltage varied within a range of 0 V to 100 V. The quantum efficiency was 10%. The results obtained led to a conclusion that EL is due to the recombination processes developing in the polymer proper, for light-emitting accompanying the sample failure belongs to a quite different spectrum area. EL arises when the polymer is in a dielectric state. There is no EL when the polymer is in a conducting state.