In an imaging device, one end of a capacitive element is connected to a second input terminal to which a reference signal Ramp is applied, and the other end of the capacitive element is connected to a voltage source during a reset operation and to a voltage source after the reset operation through a switching element. As a result, the voltage of the second input terminal is changed such that a voltage difference between the first input terminal and the second input terminal becomes a voltage guaranteeing a comparison operation after the reset operation.