A hydrogen gas dissolving apparatus 1 has a hydrogen supply unit 2 capable of supplying hydrogen gas, and a hydrogen gas dissolution module 6 for bringing the hydrogen gas supplied from the hydrogen supply unit 2 in contact with and dissolved in water. The hydrogen gas dissolution module 6 has a supply port 62 to which the hydrogen gas is supplied, a hydrogen chamber 63 communicating with the supply port 62 and filled with the hydrogen gas supplied from the supply port 62, and an exhaust port 64 communicating with the hydrogen chamber 63 and discharging the air in the hydrogen chamber 63. The exhaust port 64 is located in a lower part of the hydrogen chamber 63.