Provided is a mammography apparatus that prevents a main body from falling due to damage to a coupling connecting a ball screw, to which the main body is connected, and a motor. The mammography apparatus includes: a main body having an X-ray generator and an X-ray detector; a ball screw to which the main body is connected so as to be movable up and down; a motor rotating the ball screw so as to allow the main body to move up and down; a coupling connecting a drive shaft of the motor and the ball screw; and a brake provided at one side of the coupling. When the coupling is ruptured, the brake prevents ruptured coupling portions from being separately rotated in order to prevent a fall of the main body.