A projection display device (100) capable of providing a virtual keyboard function to the user, using a light source of a pico projector, is discussed. According to an embodiment, the projection display device includes a light source unit (110) configured to emit lights; a light combining unit (120) configured to generate a leakage light from the lights emitted by the light source (110) unit and to selectively combine the lights from the light source unit (110); an image projection unit (130) configured to project an image using the combined light from the light combining unit (120); and a virtual input unit (140) configured to project an input unit image (150) using the leakage light from the light combining unit (120).