Provided are a rear converter lens and an imaging apparatus capable of achieving favorable optical performance and an appropriate back focal length with high magnification. The rear converter lens RCL consists of, in order from the object side, four lens-groups of positive, negative, negative, and positive lens-groups. In order from the object side, a first lens-group RG1 consists of a negative lens RL11 and a positive lens RL12, a second lens-group RG2 consists of a negative lens RL21 and a positive lens RL22, a third lens-group RG3 consists of a negative lens RL31, a positive lens RL32, and a negative lens RL33, and a fourth lens-group RG4 consists of a biconvex lens RL41 and a negative lens RL42. Here, 0.22