A substrate processing method using a substrate processing apparatus includes a first step and a second step. The first step is to apply a negative voltage pulse from a pulsed power supply to be included in the apparatus. The second step is to apply floating potential for an interval of time between the negative voltage pulse and a positive voltage pulse from the pulsed power supply subsequent to the negative voltage pulse. In addition, the apparatus includes a chamber, a first electrode, a second electrode, an RF power supply, and the pulsed power supply. The second electrode is provided so that the second electrode faces the first electrode to hold a substrate. The RF power supply applies an RF voltage having a frequency of 50 MHz or higher to the second electrode. The pulsed power supply repeatedly applies a voltage waveform with the RF voltage to the second electrode.