Abstract: The present invention provides a pre-treatment apparatus for an analytical metal sample, the apparatus including (1) a treatment chamber having a sample charging port which can be opened and closed and provided at the top of the chamber, a sample discharging port which can be opened and closed and provided at the bottom of the chamber, and a gas inlet and gas outlet, (2) a sample carrying bar joined to a sample holder also used as a sputtering electrode, and provided to pass through at least one side wall of the treatment chamber so as to be substantially horizontally movable and axially rotatable, and (3) a sputtering counter electrode at least having portions arranged opposite to each other in a region not inhibiting the charge and discharge of an analytical metal sample so that the sample holder can be arranged in the counter electrode.