A glass-forming machine comprising: a plurality of molds adapted for forming glass products; cooling mechanisms adapted for exposing a cooling wind to the respective molds to individually control temperatures of the respective molds, each of the cooling mechanisms including a temperature sensor adapted for detecting a temperature of a corresponding mold, a path adapted for introducing the cooling wind to the mold, and a valve mechanism adapted for opening and closing the path, and a controlling unit adapted for controlling an opening and closing operation of the valve mechanism of each mold, based on the temperature of the mold detected by the corresponding temperature sensor, to control an air volume of the cooling wind that is introduced into the mold, wherein the controlling unit is adapted for determining an operation amount of each of the valve mechanisms by PID control, wherein the controlling unit is adapted for performing a calculation by PID control using the detected temperature of the mold extracted at a constant interval to obtain the operation amount of the valve mechanism, and an expression of the calculation includes a proportional term, an integral term, and a derivative term; wherein the integral term is a product of an accumulated value of a temperature deviation of the detected temperature with respect to a target temperature and an integral coefficient; the accumulated value of the temperature deviation is a summation of products of the temperature deviations of the detected temperatures extracted from a present time to a predetermined past time and predetermined weighting coefficients; and the weighting coefficient is set to be smaller as it corresponds to the older detected temperature. a plurality of molds adapted for forming glass products; cooling mechanisms adapted for exposing a cooling wind to the respective molds to individually control temperatures of the respective molds, each of the cooling mechanisms including a temperature sensor adapted for detecting a temperature of a corresponding mold, a path adapted for introducing the cooling wind to the mold, and a valve mechanism adapted for opening and closing the path, and a controlling unit adapted for controlling an opening and closing operation of the valve mechanism of each mold, based on the temperature of the mold detected by the corresponding temperature sensor, to control an air volume of the cooling wind that is introduced into the mold, wherein the controlling unit is adapted for determining an operation amount of each of the valve mechanisms by PID control, wherein the controlling unit is adapted for performing a calculation by PID control using the detected temperature of the mold extracted at a constant interval to obtain the operation amount of the valve mechanism, and an expression of the calculation includes a proportional term, an integral term, and a derivative term; wherein the integral term is a product of an accumulated value of a temperature deviation of the detected temperature with respect to a target temperature and an integral coefficient; the accumulated value of the temperature deviation is a summation of products of the temperature deviations of the detected temperatures extracted from a present time to a predetermined past time and predetermined weighting coefficients; and the weighting coefficient is set to be smaller as it corresponds to the older detected temperature.