To insulate the heat of an optical element forming die and to retain the forming die at all times while obtaining the adequate core accuracy between upper and lower dies without being affected by the temperature in a press forming chamber and die temperature.

An upper forming die holder 40 for holding an upper forming die 30 of the optical element forming die is fitted and fixed to a thermally insulating member 50 of ceramics by utilizing the thermal expansion and contraction effect of a fitting projecting part 42 of the upper forming die holder 40 and the thermally insulating member 50 is fitted and fixed to a fitting recessed part 66 of a cooling plate 60 by utilizing the thermal expansion and contraction effect of the fitting recessed part 66. The upper forming die holder 40 is fixed to the cooling plate 60. A lower forming die holder 120 for holding a lower forming die 32 of the optical element forming die is fitted and fixed to a thermally insulating member 110 of ceramics by utilizing the thermal expansion and contraction effect of a fitting projecting part 122 of a lower forming die holder 120 and the thermally insulating member 110 is fitted and fixed to a fitting recessed part 105 of a cooling plate 100 by utilizing the thermal expansion and contraction effect of the fitting recessed part 105. The lower forming die holder 120 is fixed to the cooling plate 100.