The present invention relates to a solid-state imaging device which can output a digital signal at high speed without a high-speed clock. A solid-state imaging device includes: pixel circuits arranged in a matrix which perform photoelectric conversion on received light; and an AD conversion unit converting the resultant signal voltage of the photoelectric conversion. The AD conversion unit includes: a reference voltage generation unit generating plural reference voltages which are different from each other within a possible range for a signal voltage; a most significant bit conversion unit that identifies a voltage section including the signal voltage from among the voltage sections each having a corresponding one of the reference voltages as a base point and determines the identified result as the value of the most significant bit of the digital signal; and a least significant bit conversion unit that converts, into the least significant bit of the digital signal, the difference voltage between the signal voltage and the reference voltage as the base point of the identified voltage section.