A solid-state image sensor includes a pixel region and peripheral circuit region arranged on a semiconductor substrate. The pixel region includes pixels. Each pixel includes a photoelectric conversion element and an amplification MOS transistor that outputs a signal corresponding to charges of the photoelectric conversion element to a column signal line. The peripheral circuit region includes a circuit that drives the pixel or processes the signal output to the column signal line. A resistance of a source region of the amplification MOS transistor is lower than a resistance of a drain region of the amplification MOS transistor.