A solid-state imaging device includes a pixel unit, a reference signal generation unit including current sources, and analog-to-digital (A/D) conversion units. The A/D conversion units include comparators and counters. Each of the A/D conversion units includes at least one of the comparators and at least one of the counters which are lined up in a column direction of the pixel unit. The current sources are lined up in a row direction of the pixel unit, and face the comparators of the A/D conversion units in the column direction of the pixel unit. The comparators of the A/D conversion units are arranged between the current sources and the counters of the A/D conversion units.