A substrate processing apparatus. The substrate processing apparatus includes a vacuum chamber having a reaction space to generate plasma in which a target substrate is located, a low frequency antenna unit located outside the reaction space to generate plasma in the reaction space, a low frequency power supply to apply low frequency power to the low frequency antenna unit, a high frequency antenna unit located outside the reaction space to generate plasma in the reaction space, and a high frequency power supply to apply high frequency power to the high frequency antenna unit. The apparatus allows the ignition of plasma to be performed efficiently via the high frequency antenna unit, and improves efficiency of inductive coupling between plasma and a low frequency antenna via the low frequency antenna unit, thereby improving plasma generation efficiency.