The present invention provides a water saving aerator that can reduce the amount of water flow and generate bubble foam water from water provided by the water delivery apparatus such as a water tap. The water saving aerator comprises a water saving disc 10 for controlling the amount of water from the water tap 200, having the through-hole 11 whose diameter is smaller than that of the water tap 200, so the water flow is injected by covering the opening of the water tap 200. A first cylinder 30 covering a diffuser object 20 is provided and a second cylinder 40 covering the first cylinder 30 is provided. The water injected from the through-hole 11 of the water saving disc 10 is diffused by the diffuser object 20, and the diffused water is received by the inner wall of the first cylinder 30. An air intake hole 33 is formed on the upper portion of the first cylinder 30, and when the air pressure of the first cylinder 30 is decreased by the water flow running into the water pass 71 between the diffuser object 20 and the first cylinder 30, the outer air is ventilated through the ventilation pass 72 formed between the first cylinder 30 and the second cylinder 40 via the air intake hole 33, the bubble form water is generated by mixing the water flow and air.