PURPOSE: To prevent noises in an output signal, by a constitution wherein the channel potential of an MOS transistor provided in a signal charge output part is higher on the side of a drain and lower on the side of a source.

CONSTITUTION: Diffused regions 3 and 4 are a source and a drain, respectively in an MOSFET. In this MOSFET, a width d2 of a signal output part 20b is narrower than a width d1 of a signal tJansfer part 20a, in which a transfer gate 5 is provided, in an embedded cahnnel 20. Parts 20c and 20d, where the diffused regions 3 and 4 are formed, respectively, have the width d2. The width of a position, where a part 20e, at which a reset gate 8 is provided' is coutnued to the part 20c, T is d33. The width d3 is narrow. In the region 20e, as the channel width becomes narrower, the channel potential becomes lower. The signal charge from the region 20e all moves to the region 20d aud does not leak to the region 20c. Therefore, noises are not generated in the output signal from a terminal 9.