A solid-state image pickup device may include: an image pickup unit in which a plurality of pixels are arranged in a matrix; a sample-and-hold unit having a switch element and a capacitance element; a frequency conversion unit in which a plurality of stages of inverting circuits are connected, the pixel signal is supplied to the first power supply terminal, and a start signal for starting clock generation and an output signal from the inverting circuit of a predetermined stage are input to one of the inverting circuits; a counting unit that counts the clock output from the frequency conversion unit; and a buffer circuit provided between a first terminal of the capacitance element connected to the switch element and the first power supply terminal, wherein a second terminal of the capacitance element is connected to the second power supply terminal.