A manufacturing method of a galvanized steel sheet, the manufacturing method comprising: circulating a coating bath which is a molten metal including a molten zinc and a molten aluminum in order of a coating tub, a separating tub, and an adjusting tub; coating a steel sheet which is dipped in the coating bath at the coating tub in which the coating bath transferred from the adjusting tub is stored at a predetermined bath temperature T1; separating by a flotation a top-dross which is precipitated at the separating tub in which the coating bath transferred from the coating tub to the separating tub is stored at a bath temperature T2 which is lower 5°C or more as compared with the bath temperature T1 of the coating tub and to be higher than a melting point of the molten metal; and dissolving a residual dross at the adjusting tub in which the coating bath transferred from the separating tub is stored at a bath temperature T3 which is higher than the bath temperature T2 of the separating tub, wherein the bath temperature T3 is controlled by a temperature controller so that the bath temperature T2 and the bath temperature T3 satisfy a following formula in Celsius degree, T 2 + 5 ≤ T 3 a first zinc-included-metal which includes an aluminum with a concentration higher than the aluminum concentration A1 of the coating bath in the coating tub is supplied to the separating tub depending on a measurement result of an aluminum concentration analyzer, a second zinc-included-metal which is a zinc-included-metal which includes an aluminum with a concentration lower than an aluminum concentration A2 of the coating bath in the separating tub or a zinc-included-metal which does not include an aluminum is supplied to the adjusting tub depending on the measurement result of an aluminum concentration analyzer, and the aluminum concentration A2 of the coating bath in the separating tub is more than 0.14 mass%, and wherein the bath temperature T1, the bath temperature T2, and the bath temperature T3 satisfy a following formula in Celsius degree, when a difference of a bath temperature decrease of the coating bath when transferred from the adjusting tub to the coating tub is ΔT fall in Celsius degree, T 1 + ΔT fall − 10 ≤ T 3 ≤ T 1 + ΔT fall + 10 a storage of the coating bath in the coating tub is five times or less of a circulating volume of the coating bath per one hour by the circulator, and a storage of the coating bath in the separating tub is two times or more of a circulating volume of the coating bath per one hour by the circulator. circulating a coating bath which is a molten metal including a molten zinc and a molten aluminum in order of a coating tub, a separating tub, and an adjusting tub; coating a steel sheet which is dipped in the coating bath at the coating tub in which the coating bath transferred from the adjusting tub is stored at a predetermined bath temperature T1; separating by a flotation a top-dross which is precipitated at the separating tub in which the coating bath transferred from the coating tub to the separating tub is stored at a bath temperature T2 which is lower 5°C or more as compared with the bath temperature T1 of the coating tub and to be higher than a melting point of the molten metal; and dissolving a residual dross at the adjusting tub in which the coating bath transferred from the separating tub is stored at a bath temperature T3 which is higher than the bath temperature T2 of the separating tub, wherein the bath temperature T3 is controlled by a temperature controller so that the bath temperature T2 and the bath temperature T3 satisfy a following formula in Celsius degree, T 2 + 5 ≤ T 3 a first zinc-included-metal which includes an aluminum with a concentration higher than the aluminum concentration A1 of the coating bath in the coating tub is supplied to the separating tub depending on a measurement result of an aluminum concentration analyzer, a second zinc-included-metal which is a zinc-included-metal which includes an aluminum with a concentration lower than an aluminum concentration A2 of the coating bath in the separating tub or a zinc-included-metal which does not include an aluminum is supplied to the adjusting tub depending on the measurement result of an aluminum concentration analyzer, and the aluminum concentration A2 of the coating bath in the separating tub is more than 0.14 mass%, and wherein the bath temperature T1, the bath temperature T2, and the bath temperature T3 satisfy a following formula in Celsius degree, when a difference of a bath temperature decrease of the coating bath when transferred from the adjusting tub to the coating tub is ΔT fall in Celsius degree, T 1 + ΔT fall − 10 ≤ T 3 ≤ T 1 + ΔT fall + 10 a storage of the coating bath in the coating tub is five times or less of a circulating volume of the coating bath per one hour by the circulator, and a storage of the coating bath in the separating tub is two times or more of a circulating volume of the coating bath per one hour by the circulator.