A structure of gas regulator comprises a space for setting an intake switchover valve formed at an outer end of a high-pressure portion and interconnected with the inside of the high-pressure portion. A pushing block is outside a diaphragm, and an elastic element is set between the pushing block and a flange at the periphery of an inner end of the pushing block. A support base outside the pushing block is abutted the elastic element and comprises an extending section extended from an inner end thereof and corresponding to the outer periphery of the elastic element and a through-hole corresponding to the pushing block. A display diaphragm with a center slot is outside the support base. A cover covered the space has a transparent side display window at the periphery thereof and a transparent outer display window at an outer end thereof.