An image pickup apparatus having a wide angle zoom lens system includes a zoom lens system, and an image pickup element which is disposed at an image side of the zoom lens system. The zoom lens system includes in order from an object side thereof, a first lens unit G1 having a positive refracting power, a second lens unit G2 having a negative refracting power, a third lens unit G3 having a positive refracting power, a fourth lens unit G4 having a positive refracting power, and an aperture stop S which is disposed between the second lens unit G2 and the third lens unit G3. A zooming is carried out from a wide angle end to a telephoto end by fixing a position of the first lens unit, and changing a distance between the lens units by moving at least the second lens unit G2 and the third lens unit G3, and the following conditional expressions are satisfied. 33°