Positioning device for side gauge of stamping machine

The invention relates to a positioning device for a side gauge of a stamping machine. The positioning device for the side gauge of the stamping machine comprises an exhaust tube, a switch assembly and a paper pulling assembly; an air releasing through hole is formed in a side wall surface of the exhaust tube; the switch assembly comprises a switch fixed piece and a switch sliding piece; the switch fixed piece is provided with an exhaust passage which communicates with the air releasing through hole; the exhaust passage extends to the surface of the switch fixed piece; the switch sliding piece is provided with a stopper; the switch sliding piece slides so that the stopper is propped against or separated from the switch fixed piece to open or close the exhaust passage; the paper pulling assembly comprises a slidable paper pulling sliding piece, and an air suction passage which communicates with the exhaust tube is formed in the paper pulling sliding piece, and extends to the top surface of the paper pulling sli