A hydrogen production system includes: a hydrogen production device connected to an electric power system and configured to produce hydrogen by electrolyzing pure water; an output control unit capable of controlling an amount of power supplied from the electric power system to the hydrogen production device according to request from the electric power system; a first pure water line for supplying pure water to the hydrogen production device; a first adjustment device capable of adjusting an amount of pure water supplied to the hydrogen production device via the first pure water line; and a first control unit configured to control the first adjustment device, based on a power amount signal indicating information on an amount of power supplied from the electric power system to the hydrogen production device.