PURPOSE: To transfer signal charge completely without giving any voltage difference between the transfer gate pulse at the sender and that of the receiver of the boundary part by changing the surface potential between CCDs with different gate structures at the boundary part concentrated.

CONSTITUTION: A CCD 9 at the sender or a CCD 10 at the receiver of a boundary part 11 with a different gate structure is formed by a CCD where the surface potential gradually changes from the deeper state to the shallow state at the boundary part 11, the surface potential difference of the CCD 9 and CCD 10 at both sides is centered to the boundary part 11, and a surface potential difference which radically changes from the shallow state to the deep state in transfer direction is formed at a boundary α of the CCD 9 and CCD 10 at both sides.