High pressure tank and method of manufacturing high pressure tank

A method of manufacturing a high pressure tank, the method comprising:

• preparing a liner having an internal space to be filled with a gas;
• by winding a fiber reinforced resin in which a fiber is impregnated with a thermosetting resin around an outer side of the liner, forming a fiber reinforced resin layer which is a layer of the fiber reinforced resin on the outer side of the liner, and a resin layer which is a layer formed of a portion of the thermosetting resin on an outer surface of the fiber reinforced resin layer;
• increasing a temperature of the fiber reinforced resin layer and the resin layer to a predetermined temperature which is a temperature at which the thermosetting resin is cured;
• causing, in at least a period of a period during which the increasing of the temperature is performed, a pressure in the liner to be regulated to be a second pressure higher than a first pressure which is a pressure in the liner in the forming of the fiber reinforced resin layer and the resin layer;
• and
• maintaining the temperature of the fiber reinforced resin layer and the resin layer at the predetermined temperature after the increasing of the temperature.