Imaging device, imaging system, and mobile object

A driving method of an imaging device having a plurality of pixel units, each of the plurality of pixel units comprising:

• an output portion including an input node to receive electric charge generated through photoelectric conversion and being configured to output a signal based on a voltage of the input node;
• a reset portion controlled to turn on or off and configured to reset a voltage of the input node in an on state;
• and
• a control portion including a gate electrode configured to receive a control signal and being configured to control a capacitance of the input node to a first capacitance value and a second capacitance value, which is greater than the first capacitance value, according to the control signal, the driving method comprising:
• switching the capacitance of the input node from the second capacitance value to the first capacitance value by the control portion in a state where the reset portion is on;
• controlling the reset portion from on to off in the state where the capacitance of the input node is maintained at the first capacitance value;
• outputting the signal in the state where the capacitance of the input node is the first capacitance value;
• switching the capacitance of the input node from the first capacitance value to the second capacitance value by the control portion;
• and
• controlling the reset portion from off to on,
• wherein no signal is output during a period from a time when the capacitance of the input node is first changed from the first capacitance value to the second capacitance value after the signal is output in the state where the capacitance of the input node is the first capacitance value to a time when the capacitance of the input node is changed from the second capacitance value to the first capacitance value.