Secondary current detecting and judging device of resistance welding machine

The utility model discloses a secondary current detecting and judging device of a resistance welding machine. The secondary current detecting and judging device of the resistance welding machine comprises a detecting retaining circuit for detecting welding secondary current, a comparison control circuit, a relay K1 and a digital-display controller; the detecting retaining circuit, the comparison control circuit, the relay K1 and the digital-display controller are electrically connected to one another; the comparison control circuit follows up an external triggering pulse signal to control switch-on and switch-off of a contact of the relay K1, so that detecting retaining of the detecting retaining circuit on the secondary current is controlled; and a detecting retaining signal of the detecting retaining circuit is transmitted to the digital-display controller so as to be displayed by the digital-display controller. By the secondary current detecting and judging device of the resistance welding machine, unqualified welding products can be detected automatically, and the quality of welding products is kept.