In a substrate processing apparatus for processing a substrate, a processing chamber accommodating the substrate is provided. A mounting table is disposed in the processing chamber and configured to attract and hold the substrate using an electrostatic attractive force. A charge amount measurement unit is disposed in the processing chamber and configured to measure charge amount of a substrate attraction surface of the mounting table. A charge neutralization mechanism is configured to neutralize the substrate attraction surface of the mounting table. A retreating mechanism is configured to make the charge amount measurement unit retreat from a measurement position facing the substrate attraction surface of the mounting table.