A polarization controller adapted to output respective projection lights for a right-eye image and a left-eye image that are incident from a projector to a screen in different polarization directions, includes: a liquid crystal device adapted to change the polarization directions of the projection lights; and a controller adapted to control the liquid crystal device so that the respective projection lights for the right-eye image and the left-eye image have different polarization directions, wherein the controller performs control for mirror-reversing the polarization directions of the projection lights in the liquid crystal device according to a control signal indicating whether the projector performs mirror reversal of the right-eye image and the left-eye image, input from the projector.