A zoom optical system according to the present invention is provided with, in order from an object side thereof: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a negative refractive power; and a fourth lens group having a positive refractive power. The zoom optical system moves at least the second lens group and the third lens group for zooming operation from a wide-angle end to a telephoto end. The zoom optical system moves the third lens group for a focusing operation. The first lens group is provided with, in order from the object side of the zoom optical system, a meniscus lens having a negative refractive power whose concave surface faces an image side of the zoom optical system, a reflective optical element, and at least one lens.