An organic light emitting device including a pixel area displaying images and a peripheral area that is a peripheral portion of the pixel area is disclosed. A manufacturing method of an organic light emitting device includes: forming a switching element of the pixel area; forming a peripheral signal line in the peripheral area; forming a passivation layer on the switching element and the peripheral signal line; forming an overcoat and a remaining layer on the passivation layer; forming a transflective member and a thickness control layer on the overcoat; removing the remaining layer; forming a pixel electrode on the transflective member and the thickness control layer; forming an organic light emitting member on the pixel electrode; and forming a common electrode on the organic light emitting member. The remaining layer is maintained in the peripheral area such that the etchant is prevented from penetrating into the peripheral signal line, thereby preventing the corrosion of the peripheral signal line.