The invention provides a projector for achieving display of an image by an proximity projection by an extremely short distance and display of an image by a projection by middle and long distances, provides a projection unit used for the projector, and provides an electronic blackboard which can reduce weight, reduce power consumption and costs, and suppress a depth size with increased convenience. The projector includes: a body part (2) that includes an emission optical system for emitting image light; and a projection unit (3) that projects the image light emitted from the emission optical system toward an illuminated plane. The projection unit (3) includes: a variable power optical system that varies a magnification of an image with the image light; and an angle-widening mirror that reflects the image light from the variable power optical system to widen an angle. In the projector, the variable power optical system varies the magnification of an image that forms an image plane inclined to the optical axis of the emission optical system.