A gas purification system may include: a circulation gas pipe in which a second end is connected at a first position to a second pipe through which gas is supplied from a gas supply source; a booster pump; a gas purification unit; a first tank in the circulation gas pipe; a first valve positioned between the gas supply source and the first position, the first valve having an open position and a closed position; and a second valve positioned between the first tank and the second end, the second valve having an open position and a closed position, the second valve configured to be in the closed position when the first valve is in the open position.