The projection zoom lens essentially consists of a positive first lens group fixed while changing magnification and the second lens group through the fourth lens group which move while changing magnification, and a fifth lens group fixed while changing magnification; and an aperture stop positioned between adjacent moving lens groups or within one moving lens group, whereinthe numerical number of the zoom lens is set to be constant over the entire zoom range,the reduction side is configured to be telecentric, andthe projection zoom lens satisfies conditional formulas (4) and (5): 2.0