A zoom lens comprising a plurality of lens units which consists of, in order from an object side to an image side: a first lens unit which is arranged closest to the object side and is not moved for zooming; a middle lens unit comprising three or more lenses and having a negative refractive power, the middle lens unit being moved during zooming; a first rear lens unit which is moved during zooming; a second rear lens unit which is moved during zooming; and a third rear lens unit which is not moved for zooming, wherein: the zoom lens comprises an aperture stop between the middle lens unit and the first rear lens unit, the first lens unit comprises four or more lenses,, and has a positive refractive power; the zoom lens conducts focusing with a part of lenses included in the first lens unit; and the following expressions are satisfied: − 0.80 < Mr2/fr2 < 0.45; − 2.0 < Mr2/fw < 0.3; and − 15.0 < Mr1/Mr2 < 2.0, 0.44 < fr1/fr2 < 4.91, where Mr1 represents a difference between positions of the first rear lens unit at a wide angle end and a telephoto end in an optical axis direction, Mr2 represents a difference between positions of the second rear lens unit at the wide angle end and the telephoto end in the optical axis direction, fr1 represents a focal length of the first rear lens unit, fr2 represents a focal length of the second rear lens unit, fw represents a focal length of the zoom lens at the wide angle end, Mr1 has a positive sign when the first rear lens unit is positioned on the image side at the telephoto end with respect to the wide angle end, and Mr2 has a positive sign when the second rear lens unit is positioned on the image side at the telephoto end with respect to the wide angle end. a first lens unit which is arranged closest to the object side and is not moved for zooming; a middle lens unit comprising three or more lenses and having a negative refractive power, the middle lens unit being moved during zooming; a first rear lens unit which is moved during zooming; a second rear lens unit which is moved during zooming; and a third rear lens unit which is not moved for zooming, wherein: the zoom lens comprises an aperture stop between the middle lens unit and the first rear lens unit, the first lens unit comprises four or more lenses,, and has a positive refractive power; the zoom lens conducts focusing with a part of lenses included in the first lens unit; and the following expressions are satisfied: − 0.80 < Mr2/fr2 < 0.45; − 2.0 < Mr2/fw < 0.3; and − 15.0 < Mr1/Mr2 < 2.0, 0.44 < fr1/fr2 < 4.91, where Mr1 represents a difference between positions of the first rear lens unit at a wide angle end and a telephoto end in an optical axis direction, Mr2 represents a difference between positions of the second rear lens unit at the wide angle end and the telephoto end in the optical axis direction, fr1 represents a focal length of the first rear lens unit, fr2 represents a focal length of the second rear lens unit, fw represents a focal length of the zoom lens at the wide angle end, Mr1 has a positive sign when the first rear lens unit is positioned on the image side at the telephoto end with respect to the wide angle end, and Mr2 has a positive sign when the second rear lens unit is positioned on the image side at the telephoto end with respect to the wide angle end. the zoom lens comprises an aperture stop between the middle lens unit and the first rear lens unit, the first lens unit comprises four or more lenses,, and has a positive refractive power; the zoom lens conducts focusing with a part of lenses included in the first lens unit; and the following expressions are satisfied: − 0.80 < Mr2/fr2 < 0.45; − 2.0 < Mr2/fw < 0.3; and − 15.0 < Mr1/Mr2 < 2.0, 0.44 < fr1/fr2 < 4.91, where Mr1 represents a difference between positions of the first rear lens unit at a wide angle end and a telephoto end in an optical axis direction, Mr2 represents a difference between positions of the second rear lens unit at the wide angle end and the telephoto end in the optical axis direction, fr1 represents a focal length of the first rear lens unit, fr2 represents a focal length of the second rear lens unit, fw represents a focal length of the zoom lens at the wide angle end, Mr1 has a positive sign when the first rear lens unit is positioned on the image side at the telephoto end with respect to the wide angle end, and Mr2 has a positive sign when the second rear lens unit is positioned on the image side at the telephoto end with respect to the wide angle end.