To provide a method of forming an optical device by which the formed optical device is easily released from a forming mold.

In the method of forming the optical device for obtaining a glass lens 3 having a desired surface form by heating and softening optical glass of an optical material and pressing with an upper mold 1 and a lower mold 2 of a pair of the forming mold, the temperature of the mold is dropped to a fixed temperature and the mold is once opened after press-forming. In this state, the glass lens 3 is stuck on the upper mold 1 side having a convex forming surface. Then, the temperature of only the upper mold 1 is further lowered and when a pair of the forming molds reaches a fixed difference of temperature, the mold is closed again to put the glass lens 3 between a pair of the forming molds. By putting the glass lens 3 in this way, the difference of thermal expansion between the the upper surface and the lower surface of the glass lens 3 is produced to apply warping force to the glass lens 3. The sticking of the glass lens 3 to the upper mold 1 side is solved by the warping force and the glass lens 3 is taken out without being damaged.