Pressure regulation device for a liquefied natural gas storage tank, characterized in that it comprises: - a pipe for transferring boil-off gas of liquefied natural gas configured to be attached to an outlet for boil-off gas from the tank, this transfer pipe being provided with a first discharging device that is activated when the boil-off gas pressure in the tank is greater than a first predetermined threshold value, referred to as "P 1 ", - a heat exchanger for cooling and/or liquefying the boil-off gas discharged from the tank, - between the transfer pipe and the heat exchanger: - a temporary storage volume of boil-off gas and - between the storage volume and the heat exchanger: - a second discharge device designed to be activated when the boil-off gas pressure in the tank is greater than a second predetermined threshold value, greater than the first threshold value or - an expander designed to be activated when the boil-off gas pressure at the exchanger and/or tank is less than a third predetermined threshold value, referred to as "P 3 ", P 3 being less than P 1, and - a return pipe for liquefied boil-off gas connected to the heat exchanger, the return pipe being designed to be attached to an inlet for liquefied boil-off gas from the tank. - a pipe for transferring boil-off gas of liquefied natural gas configured to be attached to an outlet for boil-off gas from the tank, this transfer pipe being provided with a first discharging device that is activated when the boil-off gas pressure in the tank is greater than a first predetermined threshold value, referred to as "P 1 ", - a heat exchanger for cooling and/or liquefying the boil-off gas discharged from the tank, - between the transfer pipe and the heat exchanger: - a temporary storage volume of boil-off gas and - between the storage volume and the heat exchanger: - a second discharge device designed to be activated when the boil-off gas pressure in the tank is greater than a second predetermined threshold value, greater than the first threshold value or - an expander designed to be activated when the boil-off gas pressure at the exchanger and/or tank is less than a third predetermined threshold value, referred to as "P 3 ", P 3 being less than P 1, and - a temporary storage volume of boil-off gas and - between the storage volume and the heat exchanger: - a second discharge device designed to be activated when the boil-off gas pressure in the tank is greater than a second predetermined threshold value, greater than the first threshold value or - an expander designed to be activated when the boil-off gas pressure at the exchanger and/or tank is less than a third predetermined threshold value, referred to as "P 3 ", P 3 being less than P 1, and - a second discharge device designed to be activated when the boil-off gas pressure in the tank is greater than a second predetermined threshold value, greater than the first threshold value or - an expander designed to be activated when the boil-off gas pressure at the exchanger and/or tank is less than a third predetermined threshold value, referred to as "P 3 ", P 3 being less than P 1, and - a return pipe for liquefied boil-off gas connected to the heat exchanger, the return pipe being designed to be attached to an inlet for liquefied boil-off gas from the tank.