The present paper concerns itself with characteristics of the circulating water tank, designed and constructed at the National Fisheries University of Busan. It is an elliptical ferro-concrete water tank 12 m long, 7 m wide and 1 m deep. The experimented part of water way is 5.67 In long, 1. 76 m wide and 1m deep. For the uniform straight flow are attached stainless plates in the curved parts and stainless pipes just befor the experimental part. The speed of flow can be easily controlled by changing the electric current in armarture of motor from 0 to 30 ampere according to the method of Toulon phase shift. The speed field is uniform and deviation is 0.04 when mean speed is 0.53m/sec at 225 R. P. M. except in the areas within 6cm from the walls.