An automatic wire connecting device includes a heating electrode that heats an electrode wire by applying a current to the electrode wire, a tension applying unit that applies a tension to the electrode wire to which the current is applied by the heating electrode, a tension control unit that controls the tension applied by the tension applying unit, and a power supply control unit that applies a heating current smaller than a preset annealing current to the electrode wire until a first set time elapses since the current starts to be applied and increases the current applied to the electrode wire to reach the annealing current during a second set time after the first set time elapses since the current starts to be applied.