To provide a molten-lead liquid level control device capable of controlling a liquid level in a molten-lead container with high accuracy, and capable of keeping the level surely at a prescribed value.

A conical detection pole 5 is erected in a molten-lead container 1. Pumps 3, 4 supply and discharge molten lead to and from the molten-lead container 1. A CCD camera 6 photographs a plane region including a draft border line between the detection pole 5 and a molten-lead liquid level from an upper part of the detection pole 5. An image processing device 8 takes in an image data obtained by the camera 6, operates the area of the inside region of the draft border line and determines propriety of the liquid level of the molten lead by comparing the operated value with a reference data. The liquid level of the molten lead in the molten-lead container 1 is kept at a present value by controlling the pumps 3, 4 by a sequencer 11 based on the data of the image processing device 8.