A solid state image pickup device is provided which performs a new form of image signal reading operation. The image pickup deice comprises a semiconductor substrate and a plurality of pixels that are formed on the semiconductor substrate, with each pixel having a photodetection element, which generates signal charges upon receiving incident light, a first MOS transistor structure, which has a first floating gate that is disposed above the semiconductor substrate and a first control gate that is capacitively coupled to the first floating gate, and a second MOS transistor structure, which has a second floating gate that is disposed above the semiconductor substrate and is electrically connected to the first floating gate and a second control gate that is capacitively coupled to the second floating gate.