According to one embodiment, a projection display device comprises a light modulator configured to receive light from a light source and emit an optical image modulated based on an image signal, a projector configured to project the optical image emitted from the light modulator onto a screen, and a correction unit configured to correct a distortion of the optical image which is projected onto the screen with an optical axis of the projector being not perpendicular to the screen, wherein the correction unit corrects the optical image which is projected onto the screen so that a shape of the optical image becomes a rectangle and any one of boundary sides of a rectangular optical image is aligned with a long boundary side of a trapezoidal projectable area of the projector.