A shutter opening and closing apparatus for protecting a projection lens of a beam projector, wherein a shutter member is provided at an exterior case for selectively opening and closing an opening for exposing the light output surface of the projection lens and a driving unit mounted separately from the shutter member for driving the shutter member whereby the apparatus can be used as a wall hanging slim beam projector or a stand-up type slim beam projector capable of operating with a reduced consumption of electricity because of its compact, light-weight construction.