To provide a solid-state imaging device with short image-capturing duration. A first photodiode in a pixel in an n-th row and an m-th column is connected to a second photodiode in a pixel in an (n+1)-th row and the m-th column through a transistor. The first photodiode and the second photodiode receive light concurrently, the potential in accordance with the amount of received light is held in a pixel in the n-th row and the m-th column, and the potential in accordance with the amount of received light is held in a pixel in the (n+1)-th row and the m-th column without performing a reset operation. Then, each potential is read out. Under a large amount of light, either the first photodiode or the second photodiode is used.