PURPOSE: To provide a forming die designed to stably set a glass cob and prevent its biased or deleted shape by pressing such cob following its moving and regulation so as to constitute a continuous formed surface at each upper surface of the first and second dies of the specified forming die.

CONSTITUTION: Prior to press forming, the second die 12 is pushed down through the energetizing force of a coil spring 12 as shown in 1 (a) to form a recess 15 at the center of a bottom force 2. A glass cob G is then placed on the bottom force 2 and set at the recess 15. Thence, both upper and lower plungers 5, 6 are actuated to push the second die 12 up with a bed 16. And, the upper surface 12a of the second die 12 and that 11a of the first die 11 are continuously arranged to provide a concave forming surface 2a. Subsequently, being synchronized with this, a top force 3 is lowered to sandwich the glass cob G by the top and bottom forces 3, 2 as shown in (b) followed by pressing the cob with plungers 5, 6, thus obtaining the objective optical element, a glass lens R (C) with a specified optical surface.