ARC welding apparatus, ARC welding system, and ARC welding method

An arc welding apparatus (A1, A2) includes a difference calculating unit (U2, U6) configured to calculate a difference voltage value by subtracting a welding voltage value from a target voltage value; a speed setting unit (U3, U7) configured to set an advancing speed and a retreating speed of a welding consumable (44) with respect to a workpiece (W) to increase a ratio of a magnitude of the retreating speed to a magnitude of the advancing speed corresponding to an increase in the difference voltage value; and a driving unit (41) configured to drive the welding consumable at the advancing speed and the retreating speed to generate a short circuit condition and an arc condition.