Process intensification of a membrane rector for hydrogen production using methane steam reforming under a periodic operation was investigated via numerical simulation. In the periodic operation used, the reactor wall temperature was set to vary sinusoidally along its axis. As a result, we found that the hydrogen production rate can be increased by 7% using the appropriate wall temperature modulation. The factors of the improvement fit efficiency that give rise to the process intensification were also discussed from the viewpoint of optimizing reactions and/or transport phenomena in every part of the process.