An imaging apparatus includes a pixel that generates charge; an integral amplifier that integrates charge transferred from the pixel; a low pass filter to which output of the integral amplifier is supplied and whose time constant is variable; first and second sample-and-hold circuits that sample and hold output of the low pass filter before and after the charge is transferred from the pixel to the integral amplifier, respectively; a differential circuit that outputs a difference between signals held by the first and second sample-and-hold circuits; and a control circuit that changes the time constant. The control circuit decreases the time constant after the sampling by the first sample-and-hold circuit ends, and increases the time constant in the middle of the sampling by the second sample-and-hold circuit.