There is provided a method for producing a Cu—Ni—Sn alloy by a continuous casting method or a semi-continuous casting method, the method including pouring a molten Cu—Ni—Sn alloy from one end of a mold, both ends of which are open, and continuously drawing out the alloy as an ingot from the other end of the mold while solidifying a part of the alloy, the part being near the mold; and spraying mist-like liquid on the drawn-out ingot to cool the ingot, thereby making a cast product of the Cu—Ni—Sn alloy.