For recovering hydrogen with a high recovery from a reformed gas and contributing to downsizing and cost reduction of facilities, a high-purity hydrogen E is obtained by reforming a reformable raw material A through a reforming unit 1 to yield a hydrogen-rich reformed gas B, compressing the hydrogen-rich reformed gas B with a compressor 2, allowing the compressed gas to pass through a PSA unit 3 to remove unnecessary gases other than carbon monoxide by adsorption, and allowing the resulting gas to pass through a carbon monoxide remover 4 packed with a carbon monoxide adsorbent supporting a copper halide to remove carbon monoxide by adsorption.