According to one embodiment, a solid-state imaging device includes an imaging region, and a control circuit. An array region is rectangularly configured with a plurality of cells comprising a first photodiode, a second photodiode, a first reading transistor, a second reading transistor, a reset transistor and an amplifying transistor; a control circuit which has a first operation mode and a second operation mode, configured to perform control, in the first operation mode, of transmitting the signal charges of the first and the second photodiodes to the floating diffusion through the first andthe second reading transistors, respectively, summing up the signal charges, amplifying the potential of the floating diffusion by the amplifying transistor and outputting a signal, and configured toperform control, in the second operation mode, of transmitting the signal charge of the second photodiode to the floating diffusion through the second reading transistor, amplifying the potential of the floating diffusion by the amplifying transistor and outputting a signal.