Provided is a hydrogen refining pressure-boosting device which is durable even in a high-pressure environment. This hydrogen refining pressure-boosting device produces, from a hydrogen-containing gas, a refined hydrogen gas having higher pressure and higher purity than the hydrogen-containing gas. The hydrogen refining pressure-boosting device is equipped with multiple stacked cell structures, and a pressing structure that applies tightening stress in the direction in which the cell structures are stacked. In this hydrogen refining pressure-boosting device the flow path surface of a cathode-side separator is sized so as to be contained on the inside of the flow path surface of an anode-side separator, in the direction of a plane parallel to a solid polymer electrolyte membrane.