PURPOSE: To provide a pump operation controller which can estimate the change of water level of a pump well and can effectively control the water level by using an operation control circuit which starts or stops the operation of a pump when the estimated water level of the pump well outputted from a pump well level estimation arithmetic circuit exceeds a prescribed level.

CONSTITUTION: The signal sent from a water level detector 4 installed at a plant where the waste water is sent to a waste water treatment facility 3 from a pump well 1 via the pumps 2A and 2B is inputted to a water level detection means 6 of an automatic pump control part 5. The signal detected by the means 6 is sent to a pump number control part 7. At the same time, an inflow detector 8 is placed at a sewer pipe of an upstream part to detect the capacity of the water flowing into the well 1. Then the signal of the detector 8 is inputted to a flow rate detection means 10, and the signal detected by the means 10 is sent to a water level estimation decision part 11. The inflow is integrated and the water level of the well 1 is calculated after a fixed time, and the decision result of the pump additional start propriety is outputted. Thus, the operations of unnecessary pumps can be prevented.