To obtain a photographing optical system having a vibration-proof function and optical equipment using the photographing optical system having high optical performance over an entire object distance and capable of easily correcting image blur caused by the shake of the optical system while excellently compensating chromatic aberration.

This photographing optical system is provided with a 1st lens group having positive refractive power, a 2nd lens group having negative refractive power and a 3rd lens group having positive refractive power in order from an object side. In the optical system, the 2nd lens group is moved to an image side on an optical axis in the case of focusing from an infinity object to a short-distance object. Then, the 1st lens group has a diffraction optical surface having positive refractive power and rotationally symmetric with respect to the optical axis, and the 3rd lens group has a 3N-th lens group having negative refractive power, and the image blur is corrected by moving the 3N-th lens group in a nearly perpendicular direction to the optical axis.