A hydrogen generating apparatus for effectively generating hydrogen from ammonia and relates to the hydrogen generating apparatus for generating hydrogen from ammonia. The apparatus comprises an ammonia oxidation part having ammonia oxidation catalysts which oxidizes ammonia, and an ammonia decomposition part having an ammonia decomposition catalyst which decomposes ammonia to generate nitrogen and hydrogen. The decomposition part is located downstream of the oxidation part in a direction of feed gas flow. The oxidation catalyst contains both a noble metal catalyst and a base metal catalyst, and a loading concentration of the noble metal catalyst in an upstream portion of the oxidation part is higher than a loading concentration of the noble metal catalyst in a downstream portion of the oxidation part, and/or the decomposition catalyst contains both a noble metal catalyst and a base metal catalyst, and a loading concentration of the noble metal catalyst in a downstream portion of the decomposition part is higher than a loading concentration of the noble metal catalyst in an upstream portion of the decomposition part.