According to one embodiment, a solid-state imaging device includes an analog-to-digital conversion circuit which subjects a first and a second pixel voltages from pixels to first and second signal processing, and outputs a digital value corresponding to a difference value between the first pixel voltage and the second pixel voltage, a reference voltage generation circuit which outputs reference voltages having first and second pulse waveforms to the analog-to-digital conversion circuit. The reference voltage generation circuit includes an integration circuit. In the first signal processing which compares the reference voltage with the first pixel voltage, the reference voltage generation circuit supplies a first current to the integration circuit, and generates the first pulse waveform, after the first signal processing, the reference voltage generation circuit supplies a second current to the integration circuit, and returns a voltage value of the first pulse waveform to an initial value.