A wide-angle optical system comprises, in order from its object side, a stop, a first lens (L1) having positive refracting power, a second lens (L2) having negative refracting power and a third lens (L3) that is an aspheric lens. The third lens is configured such that as viewed in a lens section including an optical axis, a portion thereof near the optical axis is in a meniscus shape convex on an object side thereof, and an object side surface and an image side surface thereof at a peripheral site are in a meniscus shape convex on an image side thereof. The optical system satisfies the following conditions (1-1) and (1-2). −0.40