A photoelectric conversion device is configured to include a light receiving region, for converting light to signal charges, and transistors. An insulation film is arranged on a surface of the light receiving region and under gate electrodes of the transistors. A first reflection prevention film of a refractive index higher than that of the insulation film is arranged at least above the light receiving region, to sandwich the insulation film between the first reflection prevention film and the light receiving region, and includes a silicon nitride film. An interlayer insulation film is arranged on the first reflection prevention film, and a second reflection prevention film is laminated between the first reflection prevention film and the interlayer insulation film. At least one of side walls of the gate electrodes of the transistors includes the silicon nitride film and a silicon oxide film arranged between the silicon nitride film and the gate electrodes. A transistor having a gate electrode with such a side wall includes a source or drain region of an LDD structure, in which a heavily doped region of the source or drain region of the LDD structure is self aligned to the side wall formed from the silicon nitride film and the silicon oxide film.