A projection zoom lens is provided and includes: in order from the magnification side, a positive first lens group performing focusing with being fixed during power-varying and having a focusing function; a negative second lens group, a negative third lens group, and a positive fourth lens group, which are moved with correlation during the power-varying; and a positive fifth lens group G5 fixed during the power-varying. An aperture diaphragm is fixed between the fourth lens group and the fifth lens group during the power-varying. In addition, the expression of 1.7