An image sensor 20A contains a photodiode array portion 21, a signal processor 22, a switching instruction part 23A and a control part 24A. Each switch SWn is provided between the corresponding photodiode PDn and the common output line L, and instructed to carry out the switching operation by the switching instruction part 23A so as to be closed, whereby the charges accumulated in the junction capacitance portion of the photodiode PDn are output to the common output line L. On the basis of the instruction from the switching instruction part 23A, the N switches SW1 to SWN carry out the switching operation so that the N switches SW1 to SWN are set to the close state in the different periods and the interval at which each switch SWn is set to the close state is equal to an integral multiple of a base period. As described above, the charge accumulation time of each of the N photodiodes PD1 to PDN is set to an integral multiple of the base period.