The utility model discloses a metallic element automatic checkout device. The utility model discloses a system includes the arm, installs mechanical arm end's metallic element detecting instrument andthe anchor clamps part that is used for the electric -energy metering box box on the centre gripping assembly line, the anchor clamps parts are including fixed centre gripping portion that is used for centre gripping electric -energy metering box box one side and the flexible clamping part that is used for centre gripping electric -energy metering box box opposite side, fixed centre gripping portion with flexible clamping part is connected through the power equipment of a link gear that drives the seesaw of anchor clamps parts with the rear end, metallic element detecting instrument's tip includes cambered surface positioning element and plane of orientation, and cambered surface positioning element has the positioning arc face. The utility model discloses an arm replaces artifically, uses fixed centre gripping portion and flexible clamping part to carry out the coarse positioning simultaneously, adopts planar positioning's the mode and the mode of cambered surface location simultaneously again for fix a position more accurate, the validity and the reliability that guarantee to detect.