To obtain a rear converter lens which is attached to between a photographic lens and a camera main body and whose enlarging magnification is about 2, and optical equipment using the same.

This rear converter lens attachably/detachably attached to the image surface side of a principal lens system so as to enlarge the focal distance of an entire system and having a negative focal distance is constituted of 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, and the 2nd lens group is constituted of a 21st lens whose both surfaces are concave, a 22nd lens whose both surfaces are convex and a 23rd lens turning its concave surface having strong refractive power to the object side as compared with an image surface side and having negative refractive power in order from the object side. When it is assumed that a distance on the optical axis between the 2nd lens group and the 3rd lens group is BD2, and the focal distance of the rear converter lens entire system is Ft1, they satisfy 0.09<BD2/Ft1<0.20.