The present disclosure generally relates to an on-demand hydrogen gas generation device, suitable for use in a fuel cell, which utilizes water electrolysis, and more particularly galvanic cell corrosion, and/or a chemical hydride reaction, to produce hydrogen gas. The present disclosure additionally relates to such a device that comprises a switching mechanism that has an electrical current passing therethrough and that repeatedly and reversibly moves between a first position and a second position when exposed to pressure differential resulting from hydrogen gas generation, in order to (1) alter the rate at which hydrogen gas is generated, such that hydrogen gas is generated on an as-needed basis for a fuel cell connected thereto, and/or (2) ensure a substantially constant flow of hydrogen gas is released therefrom. The present disclosure additionally or alternatively relates to such an on-demand hydrogen gas generation device that comprises a gas management system designed to maximize the release or evolution of hydrogen gas, and in particular dry hydrogen gas, therefrom once it has been formed, thus maximizing hydrogen gas output. The present disclosure is still further directed to a fuel cell comprising such an on-demand hydrogen gas generation device, and in particular a fuel cell designed for small-scale applications.