An embodiment of the present invention provides an oily water separation apparatus. The oily water separation apparatus according to the embodiment of the present invention comprises a first slop tank and a second slop tank which accommodate at least one of oil and water; a first inlet line and a second inlet line which are respectively connected to the first slop tank and the second slop tank to supply oily water; a first transport line which has one side connected to a lower end portion of the first slop tank and the other side connected to the second slop tank so that the water separated from the first slop tank is moved to the second slop tank; and a second transport line which has one side connected to a lower end portion of the second slop tank and the other side connected to the first slop tank so that the water separated from the second slop tank is moved to the first slop tank. The first inlet line and the second inlet line are selectively opened so that one of the first slop tank and the second slop tank can be used as an oily water separation tank and the other one can be used as a water storage tank.
