Provided is an optical system, including, in order from an object side to an image side: a front group having a negative refractive power; an aperture stop; and a rear group having a positive refractive power, in which: the front group consists of in order from the object side to the image side: a negative first lens (L1) having a concave surface facing the image side; a second lens (L2); and a third lens (L3); the rear group consists of, in order from the object side to the image side: a positive fourth lens (L4); and a negative cemented lens (L56), which is obtained by cementing a positive fifth lens (L5) and a negative sixth lens (L6); and a focal length f56 of the cemented lens (L56) and a focal length f of the optical system are each appropriately set.