A neutralization/water separation device for an esterified product, comprising: a neutralization tank in which a crude product mixture containing alcohol and an ester compound, a neutralizing agent, and water are put to produce a neutralized mixture ; a water separation tank disposed below the neutralization tank to divide the neutralization mixture into a floating layer and an aqueous layer ; a partition wall extending downward from a ceiling of the water separation tank to provide a lower passage in the water separation tank ; and a transfer line connected to a bottom surface of the neutralization tank configured to transfer the neutralized mixture from the neutralization tank to the water separation tank , wherein the water separation tank comprises: a first water separation part into which the neutralized mixture is introduced from the neutralization tank through the transfer line ; and a second water separation part into which the neutralized mixture is introduced from the first water separation part through the lower passage , wherein the first water separation part and the second water separation part are partitioned by the partition wall ; wherein a bottom surface of the water separation tank is gradually inclined downward toward a center thereof; wherein the water separation tank is provided in plurality and the plurality of water separation tanks are connected in parallel to the neutralization tank . a neutralization tank in which a crude product mixture containing alcohol and an ester compound, a neutralizing agent, and water are put to produce a neutralized mixture ; a water separation tank disposed below the neutralization tank to divide the neutralization mixture into a floating layer and an aqueous layer ; a partition wall extending downward from a ceiling of the water separation tank to provide a lower passage in the water separation tank ; and a transfer line connected to a bottom surface of the neutralization tank configured to transfer the neutralized mixture from the neutralization tank to the water separation tank , wherein the water separation tank comprises: a first water separation part into which the neutralized mixture is introduced from the neutralization tank through the transfer line ; and a second water separation part into which the neutralized mixture is introduced from the first water separation part through the lower passage , wherein the first water separation part and the second water separation part are partitioned by the partition wall ; wherein a bottom surface of the water separation tank is gradually inclined downward toward a center thereof; a first water separation part into which the neutralized mixture is introduced from the neutralization tank through the transfer line ; and a second water separation part into which the neutralized mixture is introduced from the first water separation part through the lower passage , wherein the first water separation part and the second water separation part are partitioned by the partition wall ; wherein a bottom surface of the water separation tank is gradually inclined downward toward a center thereof; wherein the water separation tank is provided in plurality and the plurality of water separation tanks are connected in parallel to the neutralization tank . <EOS>