The invention provides a solid-state image pickup device and method for realizing a higher sensitivity and a higher S/N ratio especially in the low-luminance region while maintaining a wide dynamic range. Plural pixels are integrated in an array configuration on a semiconductor substrate with each pixel having photodiode PD, which receives light and generates and stores photoelectric charge, transfer transistor Tr1, which transfers such photoelectric charge from such photodiode, floating diffusion FD, which transfers such photoelectric charge through such transfer transistor, additive capacitive element Cs, which is set connected via the floating diffusion to the photodiode, capacitive coupling transistor Tr2, which combines or divides the capacitance of such floating diffusion and the capacitance of such additive capacitive element, and reset transistor Tr3, which is connected to such additive capacitive element or floating diffusion; and the capacitance of the floating diffusion is smaller than that of the photodiode.