An electrostatic precipitator that collects a collection target object contained in a gas by means of an electrostatic force, comprising: a first electrode and a second electrode that are arranged to oppose each other along a circulation direction of the gas, and that form an electrical field for charging the collection target object; and a power supply that is configured to apply a potential difference between the first electrode and the second electrode; a power supply control apparatus that is configured to control the power supply so as to perform intermittent charging by alternating repeating a charging time period and a charging pause time period; a voltage sensor that is configured to measure an output voltage of the power supply and is configured to input the measured output voltage to the power supply control apparatus; wherein in a second period of time (T2-2) after a first period of time (T2-1) passes from a time that the charging pause time period starts, the power supply control apparatus is configured to output a current command value to the power supply as to a output a current (DCBC) that is less than a current (DCON) in the charging time period and is greater than a current in the first period of time (T2-1); characterized in that the power supply control apparatus is configured to determine whether or not a slope of an output voltage decrease after a time that the charging pause time period starts becomes equal to or less than a prescribed value and in a case where the slope is determined to be equal to or less than the prescribed value, the power supply control apparatus is configured to control an output current so as to maintain an output voltage that is equal to or less than the output voltage (Vbc) in the case where the slope of the voltage waveform is equal to or less than the prescribed value of the slope and to start the second period of time (T2-2). a first electrode and a second electrode that are arranged to oppose each other along a circulation direction of the gas, and that form an electrical field for charging the collection target object; and a power supply that is configured to apply a potential difference between the first electrode and the second electrode; a power supply control apparatus that is configured to control the power supply so as to perform intermittent charging by alternating repeating a charging time period and a charging pause time period; a voltage sensor that is configured to measure an output voltage of the power supply and is configured to input the measured output voltage to the power supply control apparatus; wherein in a second period of time (T2-2) after a first period of time (T2-1) passes from a time that the charging pause time period starts, the power supply control apparatus is configured to output a current command value to the power supply as to a output a current (DCBC) that is less than a current (DCON) in the charging time period and is greater than a current in the first period of time (T2-1); characterized in that the power supply control apparatus is configured to determine whether or not a slope of an output voltage decrease after a time that the charging pause time period starts becomes equal to or less than a prescribed value and in a case where the slope is determined to be equal to or less than the prescribed value, the power supply control apparatus is configured to control an output current so as to maintain an output voltage that is equal to or less than the output voltage (Vbc) in the case where the slope of the voltage waveform is equal to or less than the prescribed value of the slope and to start the second period of time (T2-2).