To provide a hydrogen compressing device of such a structure that a cushion tank is installed between a hydrogen compression part and a hydrogen generating device, capable of supplying high-pressure hydrogen stably by monitoring the internal pressure of the cushion tank and making automatic start and stop of the operation of the hydrogen compression part.

The hydrogen compressing device is structured so that the cushion tank 61 is installed between the hydrogen generating device 60 and the hydrogen compression part 68, whereby the hydrogen gas 60a supplied from the hydrogen generating device 60 is allowed to stagnate once in the cushion tank 61 until the set suction pressure of the hydrogen compression part 68 is attained.