A solid-state image pickup device includes a pixel array having a plurality of photodiodes that are disposed in a matrix, electric charge transfer gates, and a floating diffusion (FD), and further includes a reset transistor and an amplifier transistor each shared by the four adjacent photodiodes. In the solid-state image pickup device, the photodiodes include first to fourth photodiodes. In a state where the amplifier transistor is activated, electric charge transfer gates connected respectively to the first to fourth photodiodes are sequentially turned ON and electric charges accumulated in the photodiodes are sequentially read out through the FD. Accordingly, a readout blanking period can be minimized to and signal charges can be read out at high speed. Moreover, readout signal lines need only to be provided for every two columns of the photodiodes, so that openings of the photodiodes can be increased in size.