An imaging device comprising: a plurality of pixels (110; 110A; 115) arrayed in a matrix, the plurality of pixels (110, 110A, 115) respectively including photoelectric converting portions (1, 1d) that convert light into signal charge and charge accumulation portions that accumulate the signal charge; and a control circuit, wherein the control circuit causes the pixels (110, 110A, 115) to sequentially perform, in each row or in two or more rows at a time, a pre-reset operation for initializing potentials of the charge accumulation portions, unless a trigger signal for giving an instruction for starting exposure is received, causes, after receiving the trigger signal, the plurality of pixels (110, 110A, 115) to simultaneously perform an exposure operation for accumulating the signal charge in the charge accumulation portions without causing the pixels to perform the pre-reset and while stopping any ongoing pre-reset operation up to the end of processing on the pixels of at least one row on which the pre-reset operation is performed or performing the pre-reset operation on some further rows from the at least one row on which the pre-reset operation is performed and not performing the pre-reset operation on the pixels of at least one row after the trigger signal is received, and causes, after performing the exposure operation, the plurality of pixels to perform a signal readout operation, a reset operation, and a reset-signal readout operation, wherein the control circuit is configured to start the pre-reset operation following the reset-signal readout operation and cause the pre-reset operation to be performed until the trigger signal for giving the instruction for starting exposure is received. a plurality of pixels (110; 110A; 115) arrayed in a matrix, the plurality of pixels (110, 110A, 115) respectively including photoelectric converting portions (1, 1d) that convert light into signal charge and charge accumulation portions that accumulate the signal charge; and a control circuit, wherein the control circuit causes the pixels (110, 110A, 115) to sequentially perform, in each row or in two or more rows at a time, a pre-reset operation for initializing potentials of the charge accumulation portions, unless a trigger signal for giving an instruction for starting exposure is received, causes, after receiving the trigger signal, the plurality of pixels (110, 110A, 115) to simultaneously perform an exposure operation for accumulating the signal charge in the charge accumulation portions without causing the pixels to perform the pre-reset and while stopping any ongoing pre-reset operation up to the end of processing on the pixels of at least one row on which the pre-reset operation is performed or performing the pre-reset operation on some further rows from the at least one row on which the pre-reset operation is performed and not performing the pre-reset operation on the pixels of at least one row after the trigger signal is received, and causes, after performing the exposure operation, the plurality of pixels to perform a signal readout operation, a reset operation, and a reset-signal readout operation, wherein the control circuit is configured to start the pre-reset operation following the reset-signal readout operation and cause the pre-reset operation to be performed until the trigger signal for giving the instruction for starting exposure is received.