According to one embodiment, a solid-state imaging device includes, a pixel section, a read pulse amplitude control unit which controls exposure time for which a photo diode carries out the photoelectric conversion and dividing the signal charge accumulated in the photo diode into fractions so that the fractions are read from the photo diode, a plurality of line memories to which the plurality of read signals are saved. And the device further includes an addition unit which synthesizes the plurality of read signals into one signal, the addition unit includes first determination unit which reads the signal saved to the predetermined line memory and comparing a signal level of the read signal with a predetermined level to determine whether or not to add a signal read from a different line memory to the compared signal.