The solid state image pick-up device comprises a chip wherein an object to be photographed is put directly on the back surface of the chip, a light incident on the object enters the inner portion of the chip, signal electric charges generated in the inner portion of the chip by the light, the signal electric charges are collected in a photo detective region and the photo detective region has a barrier diffusion layer adjacent thereto so as to collect the signal electric charges effectively. The above-mentioned structure of the solid state image pick-up device can provide superior features that the chip of the solid state image pick-up device is protected from the deterioration of elements included in the chip and the destruction of the elements by Electro Static Discharge, resulting in the reliability improvement of the chip.