According to one embodiment, a solid-state imaging device includes a pixel outputting a photoelectrically converted signal, an ADC circuit disposed in an edge portion of a pixel area to convert an analog signal of the pixel into a digital signal on the basis of a result of comparison between a signal level output from the pixel and a ramp wave which is a reference, and a multi-ramp-wave generating circuit generating a plurality of ramp waves with different amplitudes and combining the plurality of ramp waves to obtain the ramp wave.