An imaging apparatus determines, based on a frame interval associated with imaging of the object, the number of output values to be measured, and inputs electric signals of a given value to amplifiers to measure the determined number of output values during a time after a readout circuit performs a readout operation for the photoelectric conversion elements of one line and before the readout circuit performs a readout operation for the photoelectric conversion elements of the next one line, calculates a difference between the measured output value and a predetermined reference value, and corrects a measurement value of one line of the object by increasing or decreasing the measurement value by the difference.
