Disclosed is an organic light emitting display (OLED) apparatus which facilitates to lower a driving voltage and to improve a lifespan by optimizing a balance of electrons and holes among a plurality of stacks, wherein the OLED apparatus may include the plurality of stacks disposed between an anode and a cathode, and a plurality of charge generation layers for supplying charges to the plurality of stacks, wherein a thickness of the charge generation layer disposed relatively close to the anode is relatively larger than a thickness of the charge generation layer disposed relatively close to the cathode.