a mos solid - state imaging device having : a semiconductor substrate provided with a pair of source and drain regions in a pixel area , the pair of source and drain regions constituting part of a transistor in the pixel area ; an insulating film formed over the semiconductor substrate ; a wiring layer formed over the insulating film ; and a contact plug penetrating through the insulating film to connect either one of the pair of source and drain regions with the wiring layer , wherein a surface area of said one of the pair of source and drain regions is silicided , the surface area contacting with the contact plug , and a width of the surface area is equal to a width of the contact plug .