Disclosed herein are mammography device for X-ray photographing a breast and a method of photographing an object to be inspected using the same. The mammography device includes: a generator irradiating an X-ray; a detector facing the generator; a pressing pad moving between the generator and the detector to press an object to be inspected; a biological index deciding unit deciding a biological index of a subject; and a controller controlling a movement distance and a velocity of the pressing pad on the basis of the biological index decided in the biological index deciding unit.