A optical system including a projection lens system 102 for emitting light image to be enlarging-projected is accommodated inside a frame 1 configured with a lower case 2 and an upper case 3, a reflecting mirror 32 which enlarging-projects the image light emitted from the optical system toward a screen S or a top surface of a table T as a display plane is openably attached to a portion of the upper case of the frame, the device can be installed by a bottom surface of the lower case or one side surface thereof, a stand leg 5 is accommodated integrally with the case and extractably in the one side surface of the lower case, and the stand leg has a form (an inclination angle, a ratchet mechanism, a locking mechanism, and the like) satisfying an installation condition for vertically erected arrangement in the extracted state.