A
zoom lens includes, in order from an object side to an image side: a positive first lens unit; a negative second lens unit; a positive third lens unit; and a positive fourth lens unit, wherein the first lens unit includes a positive first lens
subunit, which does not move for focusing, a positive second lens
subunit, which moves during the focus adjustment, and a positive third lens
subunit, which does not move for focusing; and focal lengths of the first lens unit, the second lens unit, the third lens unit, a
magnification of the third lens unit U3 at a wide angle end, focal lengths of the first lens subunit, the second lens subunit appropriately satisfy certain relations.