A solid-state imaging apparatus, an imaging system and a driving method for the solid-state imaging apparatus that can reduce jaggy while increasing speed of operation for reading out signals are provided. The driving method includes a first step of storing one or more signals from the plurality of pixels in each of the plurality of first holding units; a second step of adding the signals from the plurality of pixels stored in the plurality of first holding units; and a third step of outputting the signal stored in the second holding unit, such that at least a part of a period of the first step is overlapped with a period of the third step.