An organic light emitting display device (OLED) includes a transparent substrate a first electrode formed on the transparent substrate a partition wall including first and second tapered structures having different tapers and formed on the first electrode, and an organic light emitting layer stacked on both sides of the first electrode below a level of the partition wall and a second electrode. The OLED device is manufactured by, for example, forming a first electrode on a transparent substrate, forming a partition wall having first and second tapered structures on the first electrode, and forming an organic light emitting layer and a second electrode, sequentially, on both sides of the first electrode below a level of the partition wall.