To provide an apparatus for separating and discharging oil and water, which is installed simply and inexpensively mounted in an existing intake gutter without making a large scaled civil engineering work.

The apparatus for separating and discharging the oily water is provided with a waste water pump 8 provided in the vicinity of the bottom of the intake gutter 1 and for pumping up water from the intake port 9a provided near the bottom of an intake gutter 1 and discharging to an outside drainage conduit 11, an upper limit level detector 5 provided at the upper part of the intake gutter 1, responding to only water and turning on when the water level of the intake gutter 1 reaches a prescribed upper limit level, a lower limit level detector 4 provided at the lower part of the intake gutter 1, responding to only water and turning on when the water level in the intake gutter 1 reaches a prescribed lower limit level and a control part 6, in which the output signal of the upper limit level detector 5 and the lower limit level detector 4 is inputted and by which the waste water pump 8 is operated when both output signals of the upper limit level detector 5 and the lower limit level detector 4 are on, and the water pump 8 is stopped when both output signals of the upper limit level detector 5 and the lower limit level detector 4 are off.