An image sensor including a photoelectric converter, a charge-voltage converter, a transfer transistor to transfer a charge from the photoelectric converter to the charge-voltage converter whereby potential of the charge-voltage converter changes to a first direction, an amplifier transistor to output a signal corresponding to potential of the charge-voltage converter to a column signal line, the amplifier transistor sequentially outputting, to the column signal line, noise level and light signal level, a capacitance between a control signal line and the charge-voltage converter, and a control unit to change a potential of the control signal line so that the potential of the charge-voltage converter changes to a second direction opposite to the first direction in a period in which the charge-voltage converter is in floating and which is prior to outputting the noise level.