The horizontal combination control unit 72 sets the switch SW46 in an ON state and sets the switches SW41 through SW45 in an OFF state at the horizontal combining unit 40. The addition control unit 73 sets the switches SW54 and SW56 in an ON state and sets the switches SW51 through SW53, the switch SW55 and the switches SW57 through SW59 in an OFF state at the arithmetic unit 50b. In addition, the addition control unit 73 sets the switches SW61 through SW65 in an ON state and sets the switch SW66 in an OFF state at the arithmetic unit 50b. The vertical control unit 70 stops the electric current supply from the second electric current source 26c.
As the first selection units 16 in the pixel 10 (1, 1) and the pixel 10 (3, 1) in the first column enter an ON state, the pixel signals from the pixel 10 (1, 1) and the pixel 10 (3, 1) are combined and a combined pixel signal is generated on the first vertical signal line VL1a. In addition, as the first selection units 16 in the pixel 10 (1, 2) and the pixel 10 (3, 2) in the second column enter an ON state, the pixel signals from the pixel 10 (1, 2) and the pixel 10 (3, 2) are combined and a combined pixel signal is generated on the first vertical signal line VL1b. Likewise, as the first selection units 16 in the pixel 10 (1, 3) and the pixel 10 (3, 3) in the third column enter an ON state, the pixel signals from the pixel 10 (1, 3) and the pixel 10 (3, 3) are combined and a combined pixel signal is generated on the first vertical signal line VL1c.