A photoelectric conversion apparatus has a plurality of photoelectric conversion cells. Each cell includes a semiconductor transistor having a control electrode area which in turn includes a plurality of main electrode areas for reading signals. The potential of the control electrode area is controlled to store carriers produced by optical pumping in the control electrode area, to read, from the main electrode area, a signal controlled by the storage voltage produced due to the storage, and to perform a refreshing operation to nullify the carriers stored in the control electrode area. A device is provided for performing a peak detection on the basis of signals from the main electrode area. At least one of the photoelectric conversion cells is shielded from light. The peak detection device performs the peak detection by detecting the difference between a peak signal obtained on the basis of a signal from the photoelectric conversion cells and a dark signal from the photoelectric conversion cells shielded from light.