A zoom lens including a first lens unit that has a positive refractive power, a second lens unit that has a negative refractive power, and at least one lens unit, in which the first lens unit, the second lens unit, and at least one lens unit are disposed from an object side to an image side in the above order. The first lens unit is formed of a single piece of lens element, and the zoom lens includes a positive lens on a side closest to an image. An Abbe number of the positive lens, back focuses at a wide angle end and a telescopic end, and focal lengths of the zoom lens at the wide angle end and the telescopic end are each set appropriately.