The quantum-confined Stark effect in electroluminescence (EL) spectra was observed using Al0.3Ga0.7As/GaAs symmetric coupled quantum-well (CQW) structures. The Stark shift of the transition between the ground electron state and heavy-hole state was found to be symmetrical with regard to the flatband bias for EL and for photoluminescence (PL), in which the electric field was applied in reverse direction. Circularly polarized photoluminescence excitation (CPPLE) spectroscopy was also employed to clarify the origins of optical transitions. Six transitions between electrons and light and heavy holes in the CQWs were clearly identified by PL and by polarization of CPPLE measurement.