Disclosed is a device having a piston formed in a multistage structure so as to administer a liquid into a human body. The device having a piston formed in a multistage structure so as to administer a liquid into a human body may comprise: a body having a liquid containing space formed therein, the rear end portion of the body being open, the body being configured in a streamlined or cylindrical shape, and the body having a liquid spraying opening formed in the front end portion so as to spray the liquid contained in the liquid containing space to the outside; a support portion having an inner penetration opening formed therein, one side of the support portion being connected to the rear end portion of the body; and a piston comprising a pressing member connected to the other side of the support portion and configured in a multistage structure such that, as a pressing table formed on the rear end portion of the pressing member is pressed, the pressing member successively moves forward and is contained inside
