An image sensor includes a capacitor, a low-impedance virtual battery, and a boost current source. The capacitor includes one end connected to a vertical signal line and the other end. The low-impedance virtual battery is connected to the other end of the capacitor and configured to detect a current flowing in the capacitor. The boost current source is configured to provide a boost current to the vertical signal line, the boost current being a current corresponding to the current flowing in the capacitor.