An organic light emitting display (OLED) apparatus comprising: an anode including a reflection-anode; a transparent cathode; a first charge generation layer including a first N-type charge generation layer and a first P-type charge generation layer; a second charge generation layer including a second N-type charge generation layer and a second P-type charge generation layer; a first stack, which includes at least a first emission layer, disposed between the anode and the first charge generation layer; a second stack, which includes at least a second emission layer, disposed between the first charge generation layer and the second charge generation layer; and a third stack, which includes at least a third emission layer, disposed between the second charge generation layer and the transparent cathode, wherein, when 'T1' indicates a distance from an upper surface of the reflection-anode to an interface between the first N-type charge generation layer and the first P-type charge generation layer, 'T2' indicates a distance from the interface between the first N-type charge generation layer and the first P-type charge generation layer to an interface between the second N-type charge generation layer and the second P-type charge generation layer, and 'T3' indicates a distance from the interface between the second N-type charge generation layer and the second P-type charge generation layer to an upper surface of the transparent cathode, the 'T1', 'T2', and 'T3' satisfy the following Equation 1, T 3 > T 2 > T 1 characterized in that, assuming that the total thickness of T1, T2, and T3 is 100%, T1 is within a range from 10% to 20%, T2 is within a range from 30% to 40%, and T3 is within a range from 45% to 60%. an anode including a reflection-anode; a transparent cathode; a first charge generation layer including a first N-type charge generation layer and a first P-type charge generation layer; a second charge generation layer including a second N-type charge generation layer and a second P-type charge generation layer; a first stack, which includes at least a first emission layer, disposed between the anode and the first charge generation layer; a second stack, which includes at least a second emission layer, disposed between the first charge generation layer and the second charge generation layer; and a third stack, which includes at least a third emission layer, disposed between the second charge generation layer and the transparent cathode, wherein, when 'T1' indicates a distance from an upper surface of the reflection-anode to an interface between the first N-type charge generation layer and the first P-type charge generation layer, 'T2' indicates a distance from the interface between the first N-type charge generation layer and the first P-type charge generation layer to an interface between the second N-type charge generation layer and the second P-type charge generation layer, and 'T3' indicates a distance from the interface between the second N-type charge generation layer and the second P-type charge generation layer to an upper surface of the transparent cathode, the 'T1', 'T2', and 'T3' satisfy the following Equation 1, T 3 > T 2 > T 1 characterized in that, assuming that the total thickness of T1, T2, and T3 is 100%, T1 is within a range from 10% to 20%, T2 is within a range from 30% to 40%, and T3 is within a range from 45% to 60%. T1 is within a range from 10% to 20%, T2 is within a range from 30% to 40%, and T3 is within a range from 45% to 60%.