A converter lens (RCL) has a negative refractive power, which is disposed on an image side of a master lens (ML) to make a focal length of an entire system longer than that of the master lens alone. The converter lens comprises a most image-side lens element (LT) disposed closest to an image side in the converter lens, wherein the most image-side lens element has a lens surface having a convex shape toward an image side, a lens disposed closest to an image side in the converter lens has a positive refractive power, and mN