A molten glass stirring device is provided that includes a container having an inlet through which molten glass flows in and an outlet through which molten glass flows out and a stirring mechanism having a vertically extending rotational shaft and an impeller provided on the rotational shaft to stir molten glass in the container. The molten glass stirring device further includes at least one of a first variable mechanism capable of adjusting the spacing between the impeller in the molten glass and the inner surface of the container by changing the horizontal position of the rotational shaft and a second variable mechanism capable of adjusting the spacing between the impeller in the molten glass and the surface of the molten glass by changing the vertical position of the rotational shaft.