Electric shock preventing device of alternating-current arc welding machine

The utility model relates to electric shock preventing devices, in particular to an electric shock preventing device of an alternating-current arc welding machine. The electric shock preventing device comprises main power supply control, and main power supply control provides a power supply for the welding machine; a current sampling unit samples current signals of the welding machine; a current conversion unit converts the sampled current signals into voltage signals; a voltage follower amplifies the voltage signals and inputs the voltage signals into a voltage comparator; the voltage comparator compares the voltage signals with given voltages; when the voltage signals are larger than the given voltages, a lockable comparator is turned over and locked by itself, an alarm is given out, and an output driven unit stops output. The electric shock preventing device of the alternating-current arc welding machine has the startup self-detection function, and is provided with an electric leakage detection circuit, th