A multiple-input gas adjuster includes a case having a chamber therein, an input channel, an output channel communicated with the chamber, a first input bore and a second input bore communicated with the input channel and the chamber. A pressure adjusting mechanism has a film assembly, a movable shaft to be reciprocated by the film assembly, a swing device pivoted in the case with an end thereof connected to the movable shaft and an opposite end for sealing the second input bore, and a driving device received in the first input bore and connected to the movable shaft for reciprocation to seal the first input bore. High pressure gas may flows into the first and second input bores through the input channel for pressure adjusting operation. With the action of the pressure adjusting mechanism, the present invention provides a well pressure reducing and stabilizing performance.