The first and the second sampling circuits SC1, SC2 may be formed to have the same circuit configuration. For example, each of first and second sampling circuits SC1, SC2 may include a first switch and a second switch SW1, SW2 and a capacitor between the first and second switches SW1, SW2.

The first switch S1 may be connected to the corresponding readout line LL and the operation of turn-on/turn-off is controlled by the corresponding sampling control signals SMP1, SMP2. When the first switch SW1 is turned on, the electrical signals passed through the readout line LL is able to be sampled in the sampling circuit.

The capacitor C may include a first electrode connected to the first switch SW1 and may store electrical signals delivered by the turn-on operation of the first switch SW1. As the capacitor C, for example, a metal oxide (MOS transistor) capacitor may be used, but the type of the capacitor is not limited to this.

The second switch SW2 is connected to a second electrode of the capacitor C, and the turn-on/turn-off operation is controlled in accordance with the corresponding output control signals COLE, COLO. When the second switch SW2 is turned on, the electrical signals stored in the capacitor C are able to be output.