METHOD FOR CONTROLLING PRESSURE OF GAS SUPPLY LINE

PROBLEM TO BE SOLVED: To reduce the temporary decrease of a downstream side pressure accompanied with the rapid change of gas usage in the downstream side equipment. SOLUTION: A pressure detection value PV of a pressure meter 2 is stored in a data storage file F, and the level of decrease of the pressure detection value PV is detected based on the changing amounts of the pressure detection value PV per unit time. When the level of decrease of the pressure detection value PV exceeds a threshold, a specific opening degree value corresponding to the level of the decrease of the pressure detection value PV is specified, and the opening degree of a pressure adjusting valve 1 is adjusted so as to be the specific opening degree value in place of fixed value control. Thus, the specific opening degree value is set by preliminarily detecting the opening degree capable of suppressing the lowering of the pressure detection value PV, and quickly restoring it to a pressure set value Ps so that the opening degree of the pressure adjusting valve 1 can be controlled so as to be the specific opening degree value. Thus, it is possible to suppress the lowering of the downstream side pressure, and to quickly restore the downstream side pressure to the pressure set value Ps.