A zoom lens system includes in order from an object side, a first lens unit having a negative refracting power, a second lens unit having a positive refracting power, a third lens unit having a positive refracting power, and a fourth lens unit having a negative refracting power. At the time of zooming from a wide angle end to a telephoto end, the second lens unit moves such that a distance between the first lens unit and the second lens unit decreases, and distances between the other lens units change. The first lens unit includes in order from the object side, one negative lens component having an aspheric surface at least on one surface, and one positive lens component, the fourth lens unit includes one negative lens component having a surface on the object side as a concave surface, and satisfies the following conditional expression (1) −4