A solid-state imaging apparatus includes a pixel array in which a plurality of unit cells are arranged to form a plurality of rows and a plurality of columns, wherein each of the plurality of unit cells includes a pixel, and the pixel comprising a photoelectric conversion element and an in-pixel readout circuit which outputs a signal corresponding to charges generated in the photoelectric conversion element, power is supplied to the plurality of unit cells via a power supply line and a ground line, and at least one of the plurality of unit cells includes at least a part of a capacitive element having a first electrode connected to the power supply line and a second electrode connected to the ground line.