The purpose of the present invention is to provide: a method and an apparatus for separating H2S, each of which is capable of selectively separating only H2S from a gas to be processed, said gas containing CO2 and H2S; and a hydrogen production system which uses this apparatus for separating H2S. A hydrogen production system of the present invention is provided with adsorbent filled towers (11, 21) which are filled with an H2S adsorbent that is obtained by having an activated carbon support triethanolamine, and a mixed gas at about 40 DEG C is supplied thereto via a line (28), said mixed gas containing CO2 and H2S and derived from a synthetic gas. While holding valves (12, 13) open, valves (22, 23) closed, valves (14, 15) closed and valves (24, 25) open, H2S is adsorbed from a gas to be processed in a dry state in the adsorbent filled tower (11) and H2S is desorbed in the adsorbent filled tower (21). In cases where H2S is adsorbed from the gas to be processed in the adsorbent filled tower (21) and H2S is desorbed in the adsorbent filled tower (11), the valves (12, 13, 24, 25) are held closed and the valves (22, 23, 14, 15) are held open.