An image sensor comprising: a plurality of pixels each having a photoelectric conversion unit that converts light into an electric charge, the light being incident from one side of a substrate, and an output unit (16, 17) that outputs a signal caused by the electric charge, the plurality of pixels being arranged in a first direction and a second direction intersecting the first direction; an accumulation unit commonly connected to the plurality of pixels arranged in the first direction, stacked on the photoelectric conversion unit on a side opposite to the one side of the substrate, and including a signal accumulation unit (CS1, CS2) that accumulates the signal caused by the electric charge and a noise accumulation unit (CN1, CN2) that accumulates a noise signal; a holding unit configured to accumulate the electric charge converted by the photoelectric conversion unit, a transfer unit that transfers the electric charge to the holding unit and a reset unit configured to resets the electric charge accumulated in the holding unit, wherein the noise signal is obtained from the signal at a time of resetting the electric charge accumulated in the holding unit; characterized by further comprising: a first potential line which is provided between the signal accumulation unit (CS1, CS2) and the noise accumulation unit (CN1, CN2) and to which a fixed potential is applied; a second potential line which is provided between the output unit (16, 17) and the accumulation unit and to which the fixed potential is applied; and a third potential line which is provided on the side of the substrate opposite to the side on which light is incident via the accumulation unit and an insulating film and to which the fixed potential is applied; wherein the noise signal is a reference signal indicating a reference level for the signal caused by the electric charge; wherein the first, second and third potential lines are configured to surround four sides of each of the signal accumulation unit (CS1, CS2) and the noise accumulation unit (CN1, CN2); and the noise accumulation unit (CN1, CN2) and the signal accumulation unit (CS1, CS2) are conductors. a plurality of pixels each having a photoelectric conversion unit that converts light into an electric charge, the light being incident from one side of a substrate, and an output unit (16, 17) that outputs a signal caused by the electric charge, the plurality of pixels being arranged in a first direction and a second direction intersecting the first direction; an accumulation unit commonly connected to the plurality of pixels arranged in the first direction, stacked on the photoelectric conversion unit on a side opposite to the one side of the substrate, and including a signal accumulation unit (CS1, CS2) that accumulates the signal caused by the electric charge and a noise accumulation unit (CN1, CN2) that accumulates a noise signal; a holding unit configured to accumulate the electric charge converted by the photoelectric conversion unit, a transfer unit that transfers the electric charge to the holding unit and a reset unit configured to resets the electric charge accumulated in the holding unit, wherein the noise signal is obtained from the signal at a time of resetting the electric charge accumulated in the holding unit; characterized by further comprising: a first potential line which is provided between the signal accumulation unit (CS1, CS2) and the noise accumulation unit (CN1, CN2) and to which a fixed potential is applied; a second potential line which is provided between the output unit (16, 17) and the accumulation unit and to which the fixed potential is applied; and a third potential line which is provided on the side of the substrate opposite to the side on which light is incident via the accumulation unit and an insulating film and to which the fixed potential is applied; wherein the noise signal is a reference signal indicating a reference level for the signal caused by the electric charge; wherein the first, second and third potential lines are configured to surround four sides of each of the signal accumulation unit (CS1, CS2) and the noise accumulation unit (CN1, CN2); and the noise accumulation unit (CN1, CN2) and the signal accumulation unit (CS1, CS2) are conductors. a first potential line which is provided between the signal accumulation unit (CS1, CS2) and the noise accumulation unit (CN1, CN2) and to which a fixed potential is applied; a second potential line which is provided between the output unit (16, 17) and the accumulation unit and to which the fixed potential is applied; and a third potential line which is provided on the side of the substrate opposite to the side on which light is incident via the accumulation unit and an insulating film and to which the fixed potential is applied; wherein the noise signal is a reference signal indicating a reference level for the signal caused by the electric charge; wherein the first, second and third potential lines are configured to surround four sides of each of the signal accumulation unit (CS1, CS2) and the noise accumulation unit (CN1, CN2); and the noise accumulation unit (CN1, CN2) and the signal accumulation unit (CS1, CS2) are conductors.