1. A medical image managing device used in a medical image system in which an image storage device storing medical images photographed by a photographing device as past images so as to specify an examination and a series and one or more image reference devices referring a user to the past images stored in the image storage device are connected to each other through a network, the medical image managing device comprising: examination correlating unit configured to correlate one past examination with the present examination, the correlated past examination being an examination on the past images satisfying two requirements that (1) the past examination is referred to by the image reference device correlated in advance with the photographing device among the one or more image reference devices and that (2) a patient to be photographed is the same; and series correlating unit configured to correlate series included in the present examination and the past examination correlated by the examination correlating unit with each other with reference to photographing conditions of the respective series.