A new CCD linear image sensor with 2,048 elements has been developed by introducing photodiode processed by selective oxidation and ion implantation technologies. This construction provides high quantum efficiency at visible light with smooth spectral response, an output non-uniformity of1.5% and a dark current saturation time of 20 s. A transfer efficiency of 99.999% is achieved from a two-phase buried channel CCD. Transfer loss mechanism at a transfer gate was examined and the minimum aperture time of the gate proved to be as low as 1 µs. Spatial resolution of the device is superior to conventional sensors because of sharp sensitivity profile of the photoelement.