A neutralization/water separation method for an esterified product, comprising: a step of putting a crude product mixture containing alcohol and an ester compound, a neutralizing agent, and water into a neutralization part of a neutralization/water separation tank (1b, 1c); wherein a bottom surface of the neutralization part is gradually inclined downward toward a center thereof; a step of mixing the crude product mixture, the neutralizing agent, and the water to produce a neutralized mixture, by discharging the neutralized mixture from the neutralization part and putting the neutralized mixture again into the neutralization part with a circulation pump, or by stirring the neutralized mixture using a propeller stirrer; a step of introducing the neutralization mixture into a first water separation part of a water separation part through an upper passage, wherein a first partition wall extends upward from a bottom surface to provide the upper passage of a neutralization/water separation tank (1b, 1c) and by which the neutralization part and the water separation part are partitioned; a step of introducing the neutralization mixture into a second water separation part of the water separation part through a lower passage, wherein a second partition wall extends downward from a ceiling of a neutralization/water separation tank (1a, 1c) to provide the lower passage, wherein the first water separation part and the second water separation part are partitioned by the second partition wall; a step of dividing the neutralization mixture into a floating layer and an aqueous layer; and a step of discharging a resultant product contained in the floating layer to the outside; wherein a bottom surface of the water separation part is gradually inclined downward toward a center thereof, and precipitated salt contained in the aqueous layer is collected to the center of the bottom surface of the water separation part, wherein the upper passage has a height of 10% to 50% of a height of the first partition wall, wherein the lower passage has a height of 10% to 50% of a height of the second partition wall. a step of putting a crude product mixture containing alcohol and an ester compound, a neutralizing agent, and water into a neutralization part of a neutralization/water separation tank (1b, 1c); wherein a bottom surface of the neutralization part is gradually inclined downward toward a center thereof; a step of mixing the crude product mixture, the neutralizing agent, and the water to produce a neutralized mixture, by discharging the neutralized mixture from the neutralization part and putting the neutralized mixture again into the neutralization part with a circulation pump, or by stirring the neutralized mixture using a propeller stirrer; a step of introducing the neutralization mixture into a first water separation part of a water separation part through an upper passage, wherein a first partition wall extends upward from a bottom surface to provide the upper passage of a neutralization/water separation tank (1b, 1c) and by which the neutralization part and the water separation part are partitioned; a step of introducing the neutralization mixture into a second water separation part of the water separation part through a lower passage, wherein a second partition wall extends downward from a ceiling of a neutralization/water separation tank (1a, 1c) to provide the lower passage, wherein the first water separation part and the second water separation part are partitioned by the second partition wall; a step of dividing the neutralization mixture into a floating layer and an aqueous layer; and a step of discharging a resultant product contained in the floating layer to the outside; wherein a bottom surface of the water separation part is gradually inclined downward toward a center thereof, and precipitated salt contained in the aqueous layer is collected to the center of the bottom surface of the water separation part, wherein the upper passage has a height of 10% to 50% of a height of the first partition wall, wherein the lower passage has a height of 10% to 50% of a height of the second partition wall.