a first semiconductor region of a first conductivity type;

a photodiode provided with a second semiconductor region of a second conductivity type disposed in said first semiconductor region and for converting light into electron charge;

a transfer transistor for transferring the electron charge from said photodiode;

a third semiconductor region of the second conductivity type to which the electron charge from said photodiode is transferred through said transfer transistor;

an isolation region disposed in the periphery of said photodiode, a gate electrode of said transfer transistor extending to overlap with the isolation region; and

a fourth semiconductor region of the first conductivity type disposed beneath said isolation region, the impurity concentration of the fourth semiconductor region being higher than that of the first semiconductor region and the gate electrode of said transfer transistor extending above at least part of the fourth semiconductor region with said isolation region interposed therebetween,

wherein the gate electrode is discrete for every pixel, and

the third semiconductor region is formed along of the gate electrode of said transfer transistor, but the width of the third semiconductor region along the edge of the gate electrode does not extend to an area where part of the gate electrode is laminated with the isolation region and the fourth semiconductor region.